The Big Bang Theory - Episode Guide

Season 1

Pilot

Episode: 1x01 | Airdate: Sep 24, 2007

Pilot

Is a comedy about brilliant physicists, Leonard and Sheldon, who are the kind of "beautiful minds" that understand how the universe works. But none of that genius helps them interact with people, especially women. All this begins to change when a free-spirited beauty named Penny moves in next door. Sheldon, Leonard's roommate, is quite content spending his nights playing Klingon Boggle with their socially dysfunctional friends, fellow Cal Tech scientists Wolowitz and Koothrappali. However, Leonard sees in Penny a whole new universe of possibilities... including love.

The Big Bran Hypothesis

Episode: 1x02 | Airdate: Oct 1, 2007

The Big Bran Hypothesis

Leonard volunteers to sign for a package, hoping to make a good impression on Penny. When he enlists the help of his obsessive-compulsive roommate, Sheldon, his attempt at chivalry goes horribly awry.

The Fuzzy Boots Corollary

Episode: 1x03 | Airdate: Oct 8, 2007

The Fuzzy Boots Corollary

Leonard is bummed to learn that his crush, Penny, is seeing someone, so encouraged by his friends and fellow scientists, Leonard actually summons the nerve to ask a woman out on a date.

The Luminous Fish Effect

Episode: 1x04 | Airdate: Oct 15, 2007

The Luminous Fish Effect

When Sheldon gets fired, he explores life beyond physics, but his initial thrill of shopping with Penny devolves over time to him weaving ponchos as a shut-in, forcing Leonard to call on Sheldon's mother.

The Hamburger Postulate

Episode: 1x05 | Airdate: Oct 22, 2007

The Hamburger Postulate

After sensing his pursuit of Penny isn't going anywhere, Leonard agrees to an unexpected sexual encounter with fellow scientist Leslie Winkle.

The Middle-Earth Paradigm

Episode: 1x06 | Airdate: Oct 29, 2007

The Middle-Earth Paradigm

Leonard, Sheldon, Wolowitz and Koothrappali undertake a challenging and risky experiment-attending the Halloween party being thrown by their hot neighbor, Penny.

The Dumpling Paradox

Episode: 1x07 | Airdate: Nov 5, 2007

The Dumpling Paradox

When Wolowitz seduces Penny's friend and takes over her apartment, Penny sleeps on Leonard and Sheldon's couch. With Wolowitz preoccupied, the guys discover they are without a fourth member of their group and in desperation, they ask Penny to join their Halo team.

The Grasshopper Experiment

Episode: 1x08 | Airdate: Nov 12, 2007

The Grasshopper Experiment

Koothrappali is overwhelmed after his parents arrange a blind date, but he discovers he actually can talk to the opposite sex after a few drinks; however, complications set in when his beautiful date is more interested in Sheldon.

The Cooper-Hofstadter Polarization

Episode: 1x09 | Airdate: Mar 17, 2008

The Cooper-Hofstadter Polarization

When Sheldon and Leonard are invited to present their joint findings at a physics conference, Sheldon refuses, and Penny steps in to mediate, only deepening the rift between the two best friends.

The Loobenfeld Decay

Episode: 1x10 | Airdate: Mar 24, 2008

The Loobenfeld Decay

After hearing Penny sing, Leonard lies to avoid seeing her perform, but Sheldon takes it one step further with a more elaborate lie that leads to the appearance of his non-existent cousin.

The Pancake Batter Anomaly

Episode: 1x11 | Airdate: Mar 31, 2008

The Pancake Batter Anomaly

When Sheldon gets sick, Leonard and the boys know what's in store and avoid him like the plague, leaving an unsuspecting Penny to nurse the world's worst patient back to health.

The Jerusalem Duality

Episode: 1x12 | Airdate: Apr 14, 2008

The Jerusalem Duality

When Leonard and Sheldon meet a 15-year-old physics prodigy, Sheldon is distraught that this boy genius is younger and smarter, so in an attempt to restore his sense of purpose, the boys come up with a solution to derail Dennis' research.

The Bat Jar Conjecture

Episode: 1x13 | Airdate: Apr 21, 2008

The Bat Jar Conjecture

Since Sheldon's only focus is to prove his mental superiority while preparing for the Physics Bowl, the guys kick him off the team and enlist his nemesis Leslie Winkle.

The Nerdvana Annihilation

Episode: 1x14 | Airdate: Apr 28, 2008

The Nerdvana Annihilation

When Leonard and the guys buy a time machine prop from a classic 1960 movie, its arrival creates problems for Penny and she tells the boys that their obsession with comics and toys is "pathetic".

The Pork Chop Indeterminacy

Episode: 1x15 | Airdate: May 5, 2008

The Pork Chop Indeterminacy

When Leonard, Wolowitz, and Koothrappali all become smitten with Sheldon's twin sister, Leonard devises a plan to eliminate his rivals, however, it backfires when Sheldon declares he will decide whom his sister dates.

The Peanut Reaction

Episode: 1x16 | Airdate: May 12, 2008

The Peanut Reaction

When Penny learns that Leonard doesn't celebrate birthdays, she attempts to throw him a surprise party, but is sidetracked by Sheldon who unexpectedly gets to live out one of his greatest fantasies at an electronics store.

The Tangerine Factor

Episode: 1x17 | Airdate: May 19, 2008

The Tangerine Factor

When Leonard asks Penny out on a date and she says yes, they each seek the "wisdom" of reluctant advisor.

Season 2

The Bad Fish Paradigm

Episode: 2x01 | Airdate: Sep 22, 2008

The Bad Fish Paradigm

After her first date with Leonard goes awry, Penny finds an unwilling confidant in Leonard's anti-social roommate, Sheldon.

The Codpiece Topology

Episode: 2x02 | Airdate: Sep 29, 2008

The Codpiece Topology

When Leonard sees Penny with a handsome new guy, he enters into a rebound relationship with Sheldon's nemesis, Leslie Winkle.

The Barbarian Sublimation

Episode: 2x03 | Airdate: Oct 6, 2008

The Barbarian Sublimation

Sheldon creates a monster when he introduces Penny to the world of online gaming.

The Griffin Equivalency

Episode: 2x04 | Airdate: Oct 13, 2008

The Griffin Equivalency

Raj, newly famous because of an article in a magazine, gets a big head and makes a disastrous play for Leonard's crush, Penny.

The Euclid Alternative

Episode: 2x05 | Airdate: Oct 20, 2008

The Euclid Alternative

Leonard and his friends stage an intervention to make Sheldon confront his longstanding fear of driving.

The Cooper-Nowitzki Theorem

Episode: 2x06 | Airdate: Nov 3, 2008

The Cooper-Nowitzki Theorem

Young grad student's attraction to Sheldon confuses everyone, including Sheldon himself.

The Panty Piñata Polarization

Episode: 2x07 | Airdate: Nov 10, 2008

The Panty Piñata Polarization

Penny vows to get revenge on Sheldon when he bans her from the apartment for a series of petty infractions.

The Lizard-Spock Expansion

Episode: 2x08 | Airdate: Nov 17, 2008

The Lizard-Spock Expansion

Wolowitz thinks he's found the love of his life, until she meets Leonard.

The White Asparagus Triangulation

Episode: 2x09 | Airdate: Nov 24, 2008

The White Asparagus Triangulation

Sheldon can barely contain his joy when Leonard starts dating a woman who meets Sheldon's exacting standards.

The Vartabedian Conundrum

Episode: 2x10 | Airdate: Dec 8, 2008

The Vartabedian Conundrum

When Leonard's relationship with a new woman starts moving too fast, he goes to Penny for advice.

The Bath Item Gift Hypothesis

Episode: 2x11 | Airdate: Dec 15, 2008

The Bath Item Gift Hypothesis

Christmas is a source of stress for Leonard - whose handsome colleague starts dating Penny - and his friends, who are being tormented by Sheldon's obsession with gift-giving etiquette.

The Killer Robot Instability

Episode: 2x12 | Airdate: Jan 12, 2009

The Killer Robot Instability

When Penny's comment about Wolowitz's love life sends him into a depressed stupor, his friends lose their most important team-mate in an upcoming fighting robot competition.

The Friendship Algorithm

Episode: 2x13 | Airdate: Jan 19, 2009

The Friendship Algorithm

Socially awkward Sheldon develops a scientific procedure for making friends.

The Financial Permeability

Episode: 2x14 | Airdate: Feb 2, 2009

The Financial Permeability

Sheldon's "simple" solution to Penny's financial problem leads to a confrontation between Leonard and Penny's hulking ex-boyfriend, Kurt.

The Maternal Capacitance

Episode: 2x15 | Airdate: Feb 9, 2009

The Maternal Capacitance

Disastrous visit from Mrs. Hofstadter brings Leonard and Penny closer together.

The Cushion Saturation

Episode: 2x16 | Airdate: Mar 2, 2009

The Cushion Saturation

Paintball game leads to a fight between Penny and Sheldon, and romance for Wolowitz and Leslie.

The Terminator Decoupling

Episode: 2x17 | Airdate: Mar 9, 2009

The Terminator Decoupling

Train trip to San Francisco takes a major detour when Leonard, Sheldon, Wolowitz and Raj discover that beautiful sci-fi actress Summer Glau is onboard.

The Work Song Nanocluster

Episode: 2x18 | Airdate: Mar 16, 2009

The Work Song Nanocluster

Penny's home hair products business becomes a complete nightmare when a caffeine-addled Sheldon takes over.

The Dead Hooker Juxtaposition

Episode: 2x19 | Airdate: Mar 30, 2009

The Dead Hooker Juxtaposition

Penny develops a rivalry with a sexy female neighbor who threatens to become "The New Penny" in the building.

The Hofstadter Isotope

Episode: 2x20 | Airdate: Apr 13, 2009

The Hofstadter Isotope

While a fellow comic book-loving pal of the guys romances Penny, Leonard and Wolowitz venture out into the world of "Ladies' Night" at a local bar.

The Vegas Renormalization

Episode: 2x21 | Airdate: Apr 27, 2009

The Vegas Renormalization

Leonard and Koothrappali take a heartbroken Wolowitz to Las Vegas, leaving Sheldon locked out of his apartment and forced to bunk with Penny.

The Classified Materials Turbulence

Episode: 2x22 | Airdate: May 4, 2009

The Classified Materials Turbulence

Things begin to look up for Leonard when Penny makes a surprising revelation on her second date with Stuart. Meanwhile, Wolowitz enlists his friends' help when he discovers a critical design flaw in his project for NASA.

The Monopolar Expedition

Episode: 2x23 | Airdate: May 11, 2009

The Monopolar Expedition

Penny is conflicted when Leonard and his friends decide to spend the summer working - at the North Pole.

Season 3

The Electric Can Opener Fluctuation

Episode: 3x01 | Airdate: Sep 21, 2009

The Electric Can Opener Fluctuation

Sheldon flees back to Texas in disgrace when he learns the guys tampered with his arctic expedition data, forcing the guys to follow him and threatening Leonard's hopes for a romantic encounter with Penny.

The Jiminy Conjecture

Episode: 3x02 | Airdate: Sep 28, 2009

The Jiminy Conjecture

Leonard and Penny struggle to recover from an awkward first hookup while Sheldon and Howard stake their best comic books on a bet to determine the species of a cricket.

The Gothowitz Deviation

Episode: 3x03 | Airdate: Oct 5, 2009

The Gothowitz Deviation

Howard and Raj visit a Goth nightclub to pick up women while Sheldon attempts to build a better Penny using chocolate-based behavior modification.

The Pirate Solution

Episode: 3x04 | Airdate: Oct 12, 2009

The Pirate Solution

Raj must find a new job or be sent back to India, but Sheldon has a solution, which leaves Leonard and Penny dealing with Howard as third wheel.

The Creepy Candy Coating Corollary

Episode: 3x05 | Airdate: Oct 19, 2009

The Creepy Candy Coating Corollary

While Sheldon settles a score with his nemesis, Wil Wheaton, Wolowitz begs Leonard to get Penny to set him up with one of her friends.

The Cornhusker Vortex

Episode: 3x06 | Airdate: Nov 2, 2009

The Cornhusker Vortex

Sheldon teaches Leonard how to understand football while a kite-fighting incident threatens Howard and Raj's friendship.

The Guitarist Amplification

Episode: 3x07 | Airdate: Nov 9, 2009

The Guitarist Amplification

An argument between Leonard and Penny proves "inconvenient" to Sheldon.

The Adhesive Duck Deficiency

Episode: 3x08 | Airdate: Nov 16, 2009

The Adhesive Duck Deficiency

With Leonard, Howard and Raj away camping in the desert, an injured Penny has only Sheldon to rely on.

The Vengeance Formulation

Episode: 3x09 | Airdate: Nov 23, 2009

The Vengeance Formulation

After he's humiliated on National Public Radio, Sheldon vows to destroy Kripke, while Wolowitz tries not to destroy his new relationship with Bernadette.

The Gorilla Experiment

Episode: 3x10 | Airdate: Dec 7, 2009

The Gorilla Experiment

Sheldon attempts to help Penny understand Leonard's work, and Wolowitz becomes jealous when Leonard starts hanging out with his new girlfriend.

The Maternal Congruence

Episode: 3x11 | Airdate: Dec 14, 2009

The Maternal Congruence

Visit from Leonard's mother delights Sheldon and horrifies Leonard.

The Psychic Vortex

Episode: 3x12 | Airdate: Jan 11, 2010

The Psychic Vortex

While Sheldon and Koothrappali attend a university mixer, Leonard is upset to discover that Penny believes in psychics.

The Bozeman Reaction

Episode: 3x13 | Airdate: Jan 18, 2010

The Bozeman Reaction

When their apartment is robbed, Leonard and Sheldon turn to their friends to create a state-of-the-art security system.

The Einstein Approximation

Episode: 3x14 | Airdate: Feb 1, 2010

The Einstein Approximation

Sheldon's search for the answer to a physics problem leads him to work at the Cheesecake Factory with Penny.

The Large Hadron Collision

Episode: 3x15 | Airdate: Feb 8, 2010

The Large Hadron Collision

Leonard can only bring one guest on a trip to see CERN's Large Hadron Collider in Switzerland on Valentine's Day.

The Excelsior Acquisition

Episode: 3x16 | Airdate: Mar 1, 2010

The Excelsior Acquisition

Sheldon winds up in traffic court when he gets a ticket because of Penny.

The Precious Fragmentation

Episode: 3x17 | Airdate: Mar 8, 2010

The Precious Fragmentation

When the guys find a ring from "The Lord of the Rings" at a garage sale, it threatens to tear them apart.

The Pants Alternative

Episode: 3x18 | Airdate: Mar 22, 2010

The Pants Alternative

Sheldon's friends come to his aid when his fear of public speaking stands between him and a coveted award.

The Wheaton Recurrence

Episode: 3x19 | Airdate: Apr 12, 2010

The Wheaton Recurrence

Fight between Leonard and Penny threatens their relationship, while Sheldon battles Wil Wheaton in bowling.

The Spaghetti Catalyst

Episode: 3x20 | Airdate: May 3, 2010

The Spaghetti Catalyst

When Leonard and Penny aren't speaking, Sheldon goes to extremes to keep them both happy.

The Plimpton Stimulation

Episode: 3x21 | Airdate: May 10, 2010

The Plimpton Stimulation

Leonard and Sheldon compete for the attention of a famous female physicist.

The Staircase Implementation

Episode: 3x22 | Airdate: May 17, 2010

The Staircase Implementation

Leonard tells Penny about how he met Sheldon for the first time...and what happened to the elevator.

The Lunar Excitation

Episode: 3x23 | Airdate: May 24, 2010

The Lunar Excitation

While Penny worries that dating Leonard has ruined her for normal guys, Wolowitz and Koothrappali search for Sheldon's perfect match online.

Season 4

The Robotic Manipulation

Episode: 4x01 | Airdate: Sep 23, 2010

The Robotic Manipulation

Penny finds herself along for the ride on Sheldon's first date ever; while Wolowitz finds a new use for a robotic arm.

The Cruciferous Vegetable Amplification

Episode: 4x02 | Airdate: Sep 30, 2010

The Cruciferous Vegetable Amplification

Sheldon realizes he won't live long enough to download his consciousness into a robot body, and attempts to extend his lifespan.

The Zazzy Substitution

Episode: 4x03 | Airdate: Oct 7, 2010

The Zazzy Substitution

The guys are concerned as Sheldon searches for an alternative to human companionship.

The Hot Troll Deviation

Episode: 4x04 | Airdate: Oct 14, 2010

The Hot Troll Deviation

An embarrassing secret of Wolowitz's comes to light, while Sheldon and Raj have a small war at work.

The Desperation Emanation

Episode: 4x05 | Airdate: Oct 21, 2010

The Desperation Emanation

Leonard realizes he's the only one without a girlfriend, while Sheldon wants to get rid of his.

The Irish Pub Formulation

Episode: 4x06 | Airdate: Oct 28, 2010

The Irish Pub Formulation

Leonard keeps an affair secret from Sheldon, Howard and Raj.

The Apology Insufficiency

Episode: 4x07 | Airdate: Nov 4, 2010

The Apology Insufficiency

Sheldon's answers during an FBI interview put Wolowitz's security clearance in jeopardy.

The 21-Second Excitation

Episode: 4x08 | Airdate: Nov 11, 2010

The 21-Second Excitation

While the guys camp in line for a screening, Penny and Bernadette invite Amy to her first slumber party.

The Boyfriend Complexity

Episode: 4x09 | Airdate: Nov 18, 2010

The Boyfriend Complexity

Penny asks Leonard to lie to her father, while Howard, Raj and Bernadette pull an all-nighter at a telescope.

The Alien Parasite Hypothesis

Episode: 4x10 | Airdate: Dec 9, 2010

The Alien Parasite Hypothesis

Amy finds she has sexual feelings for Penny's ex, while Koothrappali and Wolowitz try to prove who would be the better superhero.

The Justice League Recombination

Episode: 4x11 | Airdate: Dec 16, 2010

The Justice League Recombination

The guys find a "super" use for Penny's new boyfriend, Zack, when they enter a costume contest as the Justice League.

The Bus Pants Utilization

Episode: 4x12 | Airdate: Jan 6, 2011

The Bus Pants Utilization

Leonard's idea for a smartphone app derails his friendship with Sheldon.

The Love Car Displacement

Episode: 4x13 | Airdate: Jan 20, 2011

The Love Car Displacement

Tension runs high when everyone is staying at the same hotel for a science event and Bernadette runs into her ex-boyfriend.

The Thespian Catalyst

Episode: 4x14 | Airdate: Feb 3, 2011

The Thespian Catalyst

Sheldon hopes acting lessons from Penny will help him become a better teacher. Meanwhile, Koothrappali fantasizes about his best friend's girlfriend.

The Benefactor Factor

Episode: 4x15 | Airdate: Feb 10, 2011

The Benefactor Factor

Wealthy donor to the university makes Leonard consider how far he's willing to go for the sake of science.

The Cohabitation Formulation

Episode: 4x16 | Airdate: Feb 17, 2011

The Cohabitation Formulation

As Wolowitz contemplates taking things with Bernadette to the next level, Leonard rekindles his relationship with Raj's sister.

The Toast Derivation

Episode: 4x17 | Airdate: Feb 24, 2011

The Toast Derivation

Sheldon struggles to cope when he realizes it's actually Leonard who is the center of their social group.

The Prestidigitation Approximation

Episode: 4x18 | Airdate: Mar 10, 2011

The Prestidigitation Approximation

Leonard must choose between new girlfriend Priya and his friendship with Penny. Meanwhile, Howard drives Sheldon crazy with a magic trick.

The Zarnecki Incursion

Episode: 4x19 | Airdate: Mar 31, 2011

The Zarnecki Incursion

When someone hacks Sheldon's online game account, the guys go on a quest to find the culprit.

The Herb Garden Germination

Episode: 4x20 | Airdate: Apr 7, 2011

The Herb Garden Germination

Sheldon and Amy experiment on their friends by spreading gossip, while Howard takes a big step in his relationship with Bernadette.

The Agreement Dissection

Episode: 4x21 | Airdate: Apr 28, 2011

The Agreement Dissection

When Priya uses her lawyer skills to pick apart the roommate agreement, the girls take Sheldon dancing.

The Wildebeest Implementation

Episode: 4x22 | Airdate: May 5, 2011

The Wildebeest Implementation

Raj attempts to cure his social anxiety disorder while Penny uses Bernadette to spy on Leonard and his girlfriend.

The Engagement Reaction

Episode: 4x23 | Airdate: May 12, 2011

The Engagement Reaction

When Howard finally breaks the news to his mom that he's engaged to Bernadette, it lands her in the hospital.

The Roommate Transmogrification

Episode: 4x24 | Airdate: May 19, 2011

The Roommate Transmogrification

When Bernadette receives her Ph.D., the guys take joy in reminding an emasculated Wolowitz that he is the only one in their group who isn't a doctor. Meanwhile, Koothrappali becomes Sheldon's new roommate after hearing Leonard and Priya engaging in a "Star Trek" bedroom fantasy.

Season 5

The Skank Reflex Analysis

Episode: 5x01 | Airdate: Sep 22, 2011

The Skank Reflex Analysis

Penny worries that she's screwed things up permanently with her friends, while Sheldon takes command of the paintball team.

The Infestation Hypothesis

Episode: 5x02 | Airdate: Sep 22, 2011

The Infestation Hypothesis

Fight between Sheldon and Penny leaves Amy caught in the middle, while Leonard tries to spice up his long-distance relationship with Priya.

The Pulled Groin Extrapolation

Episode: 5x03 | Airdate: Sep 29, 2011

The Pulled Groin Extrapolation

Leonard and Amy get to know each other better, while Howard and Bernadette spend the weekend with Mrs. Wolowitz.

The Russian Rocket Reaction

Episode: 5x05 | Airdate: Oct 13, 2011

The Russian Rocket Reaction

Sheldon and Leonard get invited to a party at Wil Wheaton's house, and Howard gets an out-of-this-world opportunity.

The Rhinitis Revelation

Episode: 5x06 | Airdate: Oct 20, 2011

The Rhinitis Revelation

Sheldon competes with the gang for his mother's attention when she comes to visit.

The Good Guy Fluctuation

Episode: 5x07 | Airdate: Oct 27, 2011

The Good Guy Fluctuation

Cute comic book artist puts Leonard and Priya's relationship to the test, while Sheldon tries to scare the guys for Halloween.

The Isolation Permutation

Episode: 5x08 | Airdate: Nov 3, 2011

The Isolation Permutation

Amy is crushed when Bernadette and Penny go shopping for wedding dresses without her.

The Ornithophobia Diffusion

Episode: 5x09 | Airdate: Nov 10, 2011

The Ornithophobia Diffusion

Leonard and Penny try hanging out alone, and Sheldon must overcome his fear of birds.

The Flaming Spittoon Acquisition

Episode: 5x10 | Airdate: Nov 17, 2011

The Flaming Spittoon Acquisition

Sheldon considers taking his relationship with Amy to the next level when Stuart from the comic book store asks her out on a date.

The Speckerman Recurrence

Episode: 5x11 | Airdate: Dec 8, 2011

The Speckerman Recurrence

Leonard must face his fears after being contacted by his high school tormentor.

The Shiny Trinket Maneuver

Episode: 5x12 | Airdate: Jan 12, 2012

The Shiny Trinket Maneuver

Sheldon gets in trouble with Amy when he isn't impressed by her recent accomplishment, and Howard must come to grips with Bernadette's dislike of children.

The Recombination Hypothesis

Episode: 5x13 | Airdate: Jan 19, 2012

The Recombination Hypothesis

Everything might change when Leonard offers Penny a spur of the moment invitation to a romantic dinner for two.

The Beta Test Initiation

Episode: 5x14 | Airdate: Jan 26, 2012

The Beta Test Initiation

Leonard and Penny experiment with dating, while Raj develops a peculiar relationship with his phone's virtual assistant.

The Friendship Contraction

Episode: 5x15 | Airdate: Feb 2, 2012

The Friendship Contraction

Sheldon's selfish demands force Leonard to reconsider their friendship. Meanwhile, Wolowitz tries to pick his astronaut nickname.

The Vacation Solution

Episode: 5x16 | Airdate: Feb 9, 2012

The Vacation Solution

When Sheldon is forced to take his vacation, he goes to work with Amy in her neurobiology lab. Meanwhile, Bernadette wants Howard to sign a pre-nup.

The Rothman Disintegration

Episode: 5x17 | Airdate: Feb 16, 2012

The Rothman Disintegration

When an office at the University opens up, Sheldon must compete for it with his archenemy, Kripke. Meanwhile, a gift from Amy makes Penny uncomfortable.

The Werewolf Transformation

Episode: 5x18 | Airdate: Feb 23, 2012

The Werewolf Transformation

Sheldon's life is turned upside-down after his barber gets sick. Meanwhile, astronaut training causes Wolowitz to rethink his decision to go into space.

The Weekend Vortex

Episode: 5x19 | Airdate: Mar 8, 2012

The Weekend Vortex

Sheldon chooses to play video games with the guys rather than go with Amy to her aunt's birthday party.

The Transporter Malfunction

Episode: 5x20 | Airdate: Mar 29, 2012

The Transporter Malfunction

Penny buys Leonard and Sheldon "Star Trek" collectibles as a thank-you, leading Sheldon to be haunted by Mr. Spock. Meanwhile, Raj decides he has met the "Future Mrs. Koothrappali" after his parents set him up on a date.

The Hawking Excitation

Episode: 5x21 | Airdate: Apr 5, 2012

The Hawking Excitation

When Wolowitz gets to work with Stephen Hawking, Sheldon is willing to do anything to meet his hero.

The Stag Convergence

Episode: 5x22 | Airdate: Apr 26, 2012

The Stag Convergence

Bernadette reconsiders marrying Howard after learning about his sexual history.

The Launch Acceleration

Episode: 5x23 | Airdate: May 3, 2012

The Launch Acceleration

Reschedules Howard's mission, putting the wedding plans in jeopardy. Meanwhile, Leonard says something surprising to Penny in the bedroom.

The Countdown Reflection

Episode: 5x24 | Airdate: May 10, 2012

The Countdown Reflection

When Howard and Bernadette decide they want to be married before his NASA launch, the gang rushes to put on a wedding.

Season 6

The Date Night Variable

Episode: 6x01 | Airdate: Sep 27, 2012

The Date Night Variable

With his friends on dates, Raj must face his loneliness. Also, Wolowitz is caught in an argument between Bernadette and his mom, even while he's in space.

The Decoupling Fluctuation

Episode: 6x02 | Airdate: Oct 4, 2012

The Decoupling Fluctuation

When Sheldon learns that Penny is thinking about breaking up with Leonard, he tries to intervene. Meanwhile, in space, the other astronauts pick on Howard.

The Higgs Boson Observation

Episode: 6x03 | Airdate: Oct 11, 2012

The Higgs Boson Observation

Amy feels threatened when Sheldon hires a young female assistant, and the pressure of being in space takes its toll on Wolowitz.

The Re-Entry Minimization

Episode: 6x04 | Airdate: Oct 18, 2012

The Re-Entry Minimization

When Wolowitz returns from space, he doesn't get the hero's welcome he expected. Meanwhile, Game Night turns into a battle of the sexes.

The Holographic Excitation

Episode: 6x05 | Airdate: Oct 25, 2012

The Holographic Excitation

The gang celebrates Halloween at Stuart's comic book store. Meanwhile, Leonard seduces Penny with science.

The Extract Obliteration

Episode: 6x06 | Airdate: Nov 1, 2012

The Extract Obliteration

Sheldon's relationship with Stephen Hawking is threatened over a game of "Words with Friends," and Penny secretly enrolls in a class at the local college.

The Habitation Configuration

Episode: 6x07 | Airdate: Nov 8, 2012

The Habitation Configuration

Wolowitz struggles with moving out of his mother's house. Meanwhile, Sheldon is caught in the middle of an argument between Amy and Wil Wheaton.

The 43 Peculiarity

Episode: 6x08 | Airdate: Nov 15, 2012

The 43 Peculiarity

Howard and Raj try to get to the bottom of why Sheldon disappears every afternoon at 2:45. Meanwhile, Leonard and Penny deal with jealousy in their relationship.

The Parking Spot Escalation

Episode: 6x09 | Airdate: Nov 29, 2012

The Parking Spot Escalation

When the University reassigns Sheldon's parking spot to Wolowitz, their fight affects the whole gang.

The Fish Guts Displacement

Episode: 6x10 | Airdate: Dec 6, 2012

The Fish Guts Displacement

Sheldon tries to nurse a sick Amy back to health, while Wolowitz prepares for an upcoming fishing trip with his father-in-law.

The Santa Simulation

Episode: 6x11 | Airdate: Dec 13, 2012

The Santa Simulation

Sheldon revisits some Christmas memories during a game of Dungeons and Dragons, while Penny, Bernadette and Amy try to find a girl for Koothrappali when he joins the girls for ladies' night.

The Egg Salad Equivalency

Episode: 6x12 | Airdate: Jan 3, 2013

The Egg Salad Equivalency

Sheldon gets accused of sexual harassment at the University and winds up getting Leonard, Raj and Wolowitz in trouble.

The Bakersfield Expedition

Episode: 6x13 | Airdate: Jan 10, 2013

The Bakersfield Expedition

While the guys take a road trip to a comic book convention dressed as "Star Trek: The Next Generation" characters, the girls stay home and try to interpret a comic book.

The Cooper/Kripke Inversion

Episode: 6x14 | Airdate: Jan 31, 2013

The Cooper/Kripke Inversion

Sheldon is forced to work with Barry Kripke and faces a crisis of confidence. Meanwhile, Howard and Raj spend $1,000 on action figures of themselves.

The Spoiler Alert Segmentation

Episode: 6x15 | Airdate: Feb 7, 2013

The Spoiler Alert Segmentation

When Sheldon and Leonard fight, it affects Penny and Amy's living arrangements. Meanwhile, Raj takes care of Mrs. Wolowitz while Howard is away.

The Tangible Affection Proof

Episode: 6x16 | Airdate: Feb 14, 2013

The Tangible Affection Proof

While the guys try to give their significant others the perfect Valentine's Day, Raj and Stuart throw a "lonely people" party at the comic book store.

The Monster Isolation

Episode: 6x17 | Airdate: Feb 21, 2013

The Monster Isolation

After a terrible date, Koothrappali vows to never leave his apartment. Meanwhile, Penny actually impresses Sheldon with her acting skills.

The Contractual Obligation Implementation

Episode: 6x18 | Airdate: Mar 7, 2013

The Contractual Obligation Implementation

Leonard, Sheldon and Wolowitz speak to junior high girls about careers in science. Meanwhile, Koothrappali plans a date with Lucy.

The Closet Reconfiguration

Episode: 6x19 | Airdate: Mar 14, 2013

The Closet Reconfiguration

Howard struggles with whether or not he should open a letter from his father, and Leonard and Penny throw a "grown-up" cocktail party at the apartment.

The Tenure Turbulence

Episode: 6x20 | Airdate: Apr 4, 2013

The Tenure Turbulence

Leonard, Sheldon and Raj fight for tenure at the University, and the competition heats up when the girls get involved.

The Closure Alternative

Episode: 6x21 | Airdate: Apr 25, 2013

The Closure Alternative

Sheldon feels lost after one of his favorite TV shows gets canceled too soon and Amy tries to help him get over his compulsive need for closure. Meanwhile, Raj discovers a secret about his new love interest, Lucy.

The Proton Resurgence

Episode: 6x22 | Airdate: May 2, 2013

The Proton Resurgence

Sheldon and Leonard hire Professor Proton, the host of their favorite childhood TV show, to perform. Also, Howard and Bernadette run into trouble babysitting Raj's dog.

The Love Spell Potential

Episode: 6x23 | Airdate: May 9, 2013

The Love Spell Potential

When the girls' trip to Vegas falls through, the guys invite them to play Dungeons & Dragons, causing Sheldon and Amy's relationship to take an unexpected turn. Meanwhile, Koothrappali and Lucy go on a very awkward date.

The Bon Voyage Reaction

Episode: 6x24 | Airdate: May 16, 2013

The Bon Voyage Reaction

New success for Leonard makes Sheldon very jealous and throws Penny for a loop. Meanwhile, Koothrappali pushes Lucy too far in their relationship.

Season 7

The Hofstadter Insufficiency

Episode: 7x01 | Airdate: Sep 26, 2013

The Hofstadter Insufficiency

With Leonard away, Sheldon and Penny spend quality time together sharing intimate secrets. Also, Wolowitz helps Raj get over his ex-girlfriend.

The Deception Verification

Episode: 7x02 | Airdate: Sep 26, 2013

The Deception Verification

Leonard's friendship with Sheldon is put to the test when he returns from the North Sea. Meanwhile, Wolowitz's relationship with his mother causes an unusual threat to his masculinity.

The Scavenger Vortex

Episode: 7x03 | Airdate: Oct 3, 2013

The Scavenger Vortex

When the entire gang competes in a scavenger hunt designed by Raj, it brings out the best - and worst - in everyone.

The Raiders Minimization

Episode: 7x04 | Airdate: Oct 10, 2013

The Raiders Minimization

Sheldon seeks revenge after Amy ruins one of his favorite movies. Meanwhile, Leonard discovers a way to get Penny to do anything, and Raj and Stuart create online dating profiles.

The Workplace Proximity

Episode: 7x05 | Airdate: Oct 17, 2013

The Workplace Proximity

Sheldon must decide how much "Amy time" is too much after she takes a job at his university. Meanwhile, Howard finds himself sleeping on Raj's couch after a fight with Bernadette.

The Romance Resonance

Episode: 7x06 | Airdate: Oct 24, 2013

The Romance Resonance

Sheldon's major scientific breakthrough makes him feel like a fraud. Meanwhile, Howard's romantic gesture to Bernadette causes Penny to step up her game with Leonard.

The Proton Displacement

Episode: 7x07 | Airdate: Nov 7, 2013

The Proton Displacement

Sheldon feels slighted when Professor Proton seeks advice from Leonard instead of him, and he seeks revenge by befriending a rival science TV host, Bill Nye. Meanwhile, Raj gets jealous when Howard crashes "girls' night".

The Itchy Brain Simulation

Episode: 7x08 | Airdate: Nov 14, 2013

The Itchy Brain Simulation

Leonard tries to keep Sheldon from overreacting when a past mistake comes to light, but Sheldon punishes Leonard by making him walk a mile in his shoes. Meanwhile, Penny confronts Raj's ex-girlfriend, Lucy.

The Thanksgiving Decoupling

Episode: 7x09 | Airdate: Nov 21, 2013

The Thanksgiving Decoupling

Sheldon protests when the gang drags him to Mrs. Wolowitz's house for Thanksgiving. Meanwhile, Penny and Leonard must deal with a mistake from her past.

The Discovery Dissipation

Episode: 7x10 | Airdate: Dec 5, 2013

The Discovery Dissipation

Leonard and Amy help Sheldon cope with the shame he's feeling after his accidental contribution to science is disproved. Meanwhile, Raj must stay with Howard and Bernadette for a week.

The Cooper Extraction

Episode: 7x11 | Airdate: Dec 12, 2013

The Cooper Extraction

While Sheldon is away in Texas, everyone gathers to decorate the apartment Christmas tree, and they each realize how much he has changed their lives.

The Hesitation Ramification

Episode: 7x12 | Airdate: Jan 2, 2014

The Hesitation Ramification

When Penny's big acting break on NCIS is a bust, Leonard struggles to help her, which results in Penny asking Leonard a bold relationship question. Meanwhile, Sheldon tries to learn how to be funny and Raj tries to work on his "game" before talking to girls.

The Occupation Recalibration

Episode: 7x13 | Airdate: Jan 9, 2014

The Occupation Recalibration

Sheldon tries to relax after he is forced to take a vacation. Meanwhile, Leonard struggles to be supportive of Penny after she quits her job, and Bernadette seeks Stuart's help in replacing one of Howard's comic books.

The Convention Conundrum

Episode: 7x14 | Airdate: Jan 30, 2014

The Convention Conundrum

After the guys can't get Comic-Con tickets, Sheldon tries to hold his own convention and winds up spending a wild night with James Earl Jones. Meanwhile, the girls see if they can act like "grown-ups".

The Locomotive Manipulation

Episode: 7x15 | Airdate: Feb 6, 2014

The Locomotive Manipulation

Love is in the air when Sheldon and Amy join Howard and Bernadette for a trip to wine country. Meanwhile, Leonard and Penny must rush Raj's dog to the vet.

The Table Polarization

Episode: 7x16 | Airdate: Feb 27, 2014

The Table Polarization

Leonard buys a dining room table and it causes Sheldon to reevaluate the changes in his life. Meanwhile, Wolowitz is offered a chance to go back to space and Bernadette struggles with whether or not to encourage him.

The Friendship Turbulence

Episode: 7x17 | Airdate: Mar 6, 2014

The Friendship Turbulence

After the insults fly, Bernadette tries to broker the peace between Wolowitz and Sheldon. Meanwhile, Penny is offered an embarrassing movie role and Raj asks Amy to write to a woman on his behalf.

The Mommy Observation

Episode: 7x18 | Airdate: Mar 13, 2014

The Mommy Observation

When Sheldon visits his Mom in Houston, he is forced to confront a new reality. Meanwhile, Raj's 'Murder Mystery' party starts some fights within the gang.

The Indecision Amalgamation

Episode: 7x19 | Airdate: Apr 3, 2014

The Indecision Amalgamation

While Raj is wracked with guilt when he tries to date two women at once, Penny wrestles with whether to take a role in a cheesy movie and Sheldon is torn trying to choose between two gaming systems.

The Relationship Diremption

Episode: 7x20 | Airdate: Apr 10, 2014

The Relationship Diremption

Sheldon faces a personal crisis after deciding he's wasting his time with string theory. Meanwhile, a double date between Raj, Emily and the Wolowitzes ends in embarrassment for Howard.

The Anything Can Happen Recurrence

Episode: 7x21 | Airdate: Apr 24, 2014

The Anything Can Happen Recurrence

When Sheldon tries to be spontaneous, it leads to unexpected friction between Penny, Amy and Bernadette. Meanwhile, Raj seeks Howard's help in preparing for a date with Emily.

The Proton Transmogrification

Episode: 7x22 | Airdate: May 1, 2014

The Proton Transmogrification

Professor Proton helps Sheldon cope with grief, while Leonard turns a relationship milestone into a competition with Penny. Meanwhile, Amy and Bernadette make a "Star Wars Day" gift for the guys.

The Gorilla Dissolution

Episode: 7x23 | Airdate: May 8, 2014

The Gorilla Dissolution

Bad day causes Penny to reevaluate her life choices - including Leonard. Meanwhile, Howard and Bernadette struggle to care for Mrs. Wolowitz, and Raj gets relationship advice from Sheldon.

The Status Quo Combustion

Episode: 7x24 | Airdate: May 15, 2014

The Status Quo Combustion

Sheldon is forced to confront an uncertain future and considers a major move. Meanwhile, Raj and Emily take it to the next level, and Mrs. Wolowitz's injury is a major headache for Howard and Bernadette.

Season 8

The Locomotion Interruption

Episode: 8x01 | Airdate: Sep 22, 2014

The Locomotion Interruption

Leonard and Amy take an unexpected road trip to Arizona to pick up Sheldon. Meanwhile, Penny interviews for a job at Bernadette's company, and Howard is weirded out by Stuart's relationship with Mrs. Wolowitz.

The Junior Professor Solution

Episode: 8x02 | Airdate: Sep 22, 2014

The Junior Professor Solution

Sheldon is ordered to teach a class, and the gang is surprised when Howard signs up to take it; and tensions between Penny and Bernadette afford Amy an opportunity to play one against the other.

The First Pitch Insufficiency

Episode: 8x03 | Airdate: Sep 29, 2014

The First Pitch Insufficiency

Wolowitz is nervous after NASA asks him to throw out the first pitch at a Los Angeles Angels game. Meanwhile, Leonard and Penny try to prove Sheldon wrong after he says that he and Amy are a "superior couple".

The Hook-Up Reverberation

Episode: 8x04 | Airdate: Oct 6, 2014

The Hook-Up Reverberation

Raj's honesty about his past comes back to haunt him after his girlfriend, Emily, is cold to Penny. Also, the guys consider becoming part-owners in Stuart's comic book store.

The Focus Attentuation

Episode: 8x05 | Airdate: Oct 13, 2014

The Focus Attentuation

Amy and Bernadette accuse Penny of being a "buzzkill" after she gets an email from work during their Vegas weekend. Meanwhile, the guys try to invent something cool, but only come up with new ways to procrastinate.

The Expedition Approximation

Episode: 8x06 | Airdate: Oct 20, 2014

The Expedition Approximation

Sheldon and Raj test whether they could survive a dark-matter research expedition in a salt mine by simulating the conditions in a steam tunnel. Meanwhile, Leonard and Penny seek advice from Wolowitz and Bernadette after they fight about money.

The Misinterpretation Agitation

Episode: 8x07 | Airdate: Oct 30, 2014

The Misinterpretation Agitation

The guys try to help Penny out of an awkward work dilemma. Meanwhile, Amy and Bernadette argue over whether or not female scientists should play up their sexuality.

The Prom Equivalency

Episode: 8x08 | Airdate: Nov 6, 2014

The Prom Equivalency

When the gang recreates a high school prom on the roof the of the guys' apartment building, Sheldon feels pressure to participate in all the typical romantic traditions.

The Septum Deviation

Episode: 8x09 | Airdate: Nov 13, 2014

The Septum Deviation

When Leonard gets minor surgery on his nose, Sheldon is the one in need of sympathy. Meanwhile, Raj's parents' impending divorce causes Howard and Bernadette to work on their own marriage.

The Champagne Reflection

Episode: 8x10 | Airdate: Nov 20, 2014

The Champagne Reflection

Sheldon says a tearful goodbye to "Fun with Flags." Also, Leonard, Howard and Raj look for something significant in a dead professor's research, and Bernadette is shocked to learn her co-workers' true feelings from Penny.

The Clean Room Infiltration

Episode: 8x11 | Airdate: Dec 11, 2014

The Clean Room Infiltration

On Christmas Eve, Amy plans a traditional Victorian dinner, while Raj, Leonard and Howard scramble to remove a pigeon that flew into the clean room at the university. To prove a point to Amy, a Scrooge-like Sheldon buys her the worst possible gift.

The Space Probe Disintegration

Episode: 8x12 | Airdate: Jan 8, 2015

The Space Probe Disintegration

Wolowitz tries to distract Raj, who is anxiously awaiting data from a space probe he helped launch. Meanwhile, Sheldon and Leonard go dress shopping with Penny and Amy.

The Anxiety Optimization

Episode: 8x13 | Airdate: Jan 29, 2015

The Anxiety Optimization

The gang tries to help Sheldon when he becomes stuck in a rut at work by increasing his anxiety level. Howard teases Raj with a new game called "Cinnamon or Emily?"

The Troll Manifestation

Episode: 8x14 | Airdate: Feb 5, 2015

The Troll Manifestation

After Leonard and Sheldon co-publish a physics paper, they must defend themselves against criticism from an online bully. Also, girls' night finds Penny, Amy and Bernadette confronting embarrassing moments from their past.

The Comic Book Store Regeneration

Episode: 8x15 | Airdate: Feb 19, 2015

The Comic Book Store Regeneration

Wolowitz receives some shocking news as everyone prepares for the reopening of Stuart's comic book store. Penny teaches Sheldon how to "let it go," but can't follow her own advice after she learns something infuriating about Amy. Also, Leonard and Raj think they spot Nathan Fillion at a restaurant.

The Intimacy Acceleration

Episode: 8x16 | Airdate: Feb 26, 2015

The Intimacy Acceleration

As a joke, Sheldon and Penny try an experiment designed to make participants fall in love. Also, Leonard, Amy, Raj and Emily spend the evening trying to escape a room with a "zombie." And, after returning from Mrs. Wolowitz' funeral, Bernadette and Howard run into trouble at the airport.

The Colonization Application

Episode: 8x17 | Airdate: Mar 5, 2015

The Colonization Application

Trouble arises when Amy learns Sheldon has applied for a one-way mission to colonize Mars. Also, a trip to the pet store ends in a fight for Sheldon and Amy, Leonard surprises Penny with a very "adult" purchase, and, Raj is caught snooping in Emily's apartment.

The Leftover Thermalization

Episode: 8x18 | Airdate: Mar 12, 2015

The Leftover Thermalization

Friction ensues when a magazine fails to mention Leonard in an article about the paper he co-wrote with Sheldon. Also, a blackout at Mrs. Wolowitz's home leads to a final family dinner in her honor.

The Skywalker Incursion

Episode: 8x19 | Airdate: Apr 2, 2015

The Skywalker Incursion

When Leonard and Sheldon are invited to speak at UC Berkeley, they take a detour to try to meet an idol. Also, when Bernadette and Howard battle over the fate of his Dr. Who TARDIS, Raj and Amy offer to settle the dispute with a game of ping pong.

The Fortification Implementation

Episode: 8x20 | Airdate: Apr 9, 2015

The Fortification Implementation

When Sheldon and Amy build a blanket fort, they come to major crossroads in their relationship. Also, Wolowitz meets the half-brother he never knew he had, and when Penny is invited to appear on Wil Wheaton's podcast, she and Leonard have a huge, on-air argument.

The Communication Deterioration

Episode: 8x21 | Airdate: Apr 16, 2015

The Communication Deterioration

When Raj is asked to create a message in case a NASA mission discovers alien life, the guys fight over what he should do. Also, Penny is torn between auditioning for a movie or keeping her successful pharmaceutical sales job.

The Graduation Transmission

Episode: 8x22 | Airdate: Apr 23, 2015

The Graduation Transmission

Wolowitz questions his engineering abilities when he and Sheldon can't get a toy drone to fly. Meanwhile, a cancelled flight nearly prevents Leonard from giving the commencement address at his former high school, and Raj pits his parents against each other when his father cuts him off financially.

The Maternal Combustion

Episode: 8x23 | Airdate: Apr 30, 2015

The Maternal Combustion

Personalities collide when Sheldon and Leonard's mothers finally meet. Meanwhile, Howard finally decides to "man up" and do his fair share of the housework - but not without a little help from his friends.

The Commitment Determination

Episode: 8x24 | Airdate: May 7, 2015

The Commitment Determination

In the Season 8 finale, Leonard and Penny are pressured to set a wedding date by Sheldon, whose relationship with Amy has taken an interesting turn.

Season 9

The Matrimonial Momentum

Episode: 9x01 | Airdate: Sep 21, 2015

The Matrimonial Momentum

After driving to Vegas to get married, Penny struggles with Leonard's confession that he kissed another girl. Also, Sheldon doesn't know how to act after Amy pushes pause on their relationship.

The Separation Oscillation

Episode: 9x02 | Airdate: Sep 28, 2015

The Separation Oscillation

Leonard confronts the woman he kissed on the North Sea in an attempt to set Penny's mind at ease. Also, Sheldon films a special episode of "Fun with Flags" after his breakup with Amy, and Bernadette feels guilty about withholding a secret from Penny.

The Bachelor Party Corrosion

Episode: 9x03 | Airdate: Oct 5, 2015

The Bachelor Party Corrosion

The guys surprise Leonard with a belated bachelor-party weekend in Mexico, but their plans hit a bump in the road when they get a flat tire on the way. Meanwhile, the girls lean on Penny to tell her unsuspecting family that she and Leonard eloped.

The 2003 Approximation

Episode: 9x04 | Airdate: Oct 12, 2015

The 2003 Approximation

Sheldon learns of an impending change in his living arrangements and decides to revert back to 2003, a simpler time before he met Leonard and Penny. Also, Howard and Raj form a band to play at the Comic Book Store.

The Perspiration Implementation

Episode: 9x05 | Airdate: Oct 19, 2015

The Perspiration Implementation

The guys take a fencing lesson from Barry Kripke and Sheldon finds himself in an awkward position when Kripke expresses interest in Amy. Also, when Stuart struggles to get female customers at the Comic Book Store, Penny, Amy and Bernadette come by to help him out.

The Helium Insufficiency

Episode: 9x06 | Airdate: Oct 26, 2015

The Helium Insufficiency

In the midst of a nation-wide helium shortage, Sheldon and Leonard take desperate measures to get the supplies they need. Also, Penny and Bernadette download a dating app on Amy's phone to try and find her a new man.

The Spock Resonance

Episode: 9x07 | Airdate: Nov 5, 2015

The Spock Resonance

While being interviewed for a documentary about Spock from "Star Trek", Sheldon struggles to suppress his emotions about his recent break-up with Amy. Also, Wolowitz and Bernadette butt heads over remodeling his childhood home.

The Mystery Date Observation

Episode: 9x08 | Airdate: Nov 12, 2015

The Mystery Date Observation

When Leonard, Penny and Bernadette learn that Amy is going out on a dinner date, the trio set out to spy on her and the guy. Meanwhile, Sheldon recruits Raj and Howard to find a woman for him, since they were responsible for getting Amy and him together.

The Platonic Permutation

Episode: 9x09 | Airdate: Nov 19, 2015

The Platonic Permutation

Sheldon and Amy try hanging out as friends when they spend Thanksgiving together at the aquarium. Also, Wolowitz reluctantly agrees to volunteer at the soup kitchen with Bernadette, Raj and Emily, and Penny discovers that Leonard knows more about her than she thought.

The Earworm Reverberation

Episode: 9x10 | Airdate: Dec 10, 2015

The Earworm Reverberation

Sheldon has a revelation when he realizes why a song was stuck in his head. Also, Amy invites Dave over for dinner despite their previously awkward date, and Wolowitz and Koothrappali become obsessed with a fan of their band, "Footprints on the Moon".

The Opening Night Excitation

Episode: 9x11 | Airdate: Dec 17, 2015

The Opening Night Excitation

As the guys prepare to go to the premiere of the new Star Wars movie, Sheldon plans a special event for Amy's birthday. Also, Leonard, Wolowitz, and Koothrappali must decide who will take their extra Star Wars movie ticket.

The Sales Call Sublimation

Episode: 9x12 | Airdate: Jan 7, 2016

The Sales Call Sublimation

Penny gets more than she bargained for when Leonard agrees to meet with a psychiatrist on her behalf. Also, Sheldon and Koothrappali collaborate on an astronomical discovery, and Wolowitz and Bernadette can't believe what they are feeling after Stuart moves out.

The Empathy Optimization

Episode: 9x13 | Airdate: Jan 14, 2016

The Empathy Optimization

After having to deal with a sick Sheldon, Leonard, Penny and the gang try to treat themselves to a Sheldon-free weekend.

The Meemaw Materialization

Episode: 9x14 | Airdate: Feb 4, 2016

The Meemaw Materialization

Sheldon's thrilled when his Meemaw comes to visit, but his excitement quickly fades when she butts heads with Amy. Also, Raj meets a new girl at the comic book store who makes him question his relationship with Emily.

The Valentino Submergence

Episode: 9x15 | Airdate: Feb 11, 2016

The Valentino Submergence

Sheldon and Amy host a live Valentine's Day episode of Fun with Flags, Leonard and Penny grapple with getting older, Howard and Bernadette find a surprise in their hot tub and Raj is torn between Emily and the cute girl he met at the Comic Bookstore.

The Positive Negative Reaction

Episode: 9x16 | Airdate: Feb 18, 2016

The Positive Negative Reaction

When the gang finds out about Bernadette's pregnancy, they celebrate by singing karaoke. Also, Bernadette is concerned when Wolowitz freaks out over her pregnancy announcement, and Wolowitz is convinced he must make more money to provide for the baby.

The Celebration Experimentation

Episode: 9x17 | Airdate: Feb 25, 2016

The Celebration Experimentation

After more than nine years together, the gang finally celebrates Sheldon's birthday, surprising him with a special guest.

The Application Deterioration

Episode: 9x18 | Airdate: Mar 10, 2016

The Application Deterioration

Leonard, Sheldon, and Wolowitz run into problems when they file for a patent for their infinite persistence gyroscope. Also, Penny, Amy and Bernadette give Koothrappali dating advice when Emily reaches out to him after their breakup.

The Solder Excursion Diversion

Episode: 9x19 | Airdate: Mar 31, 2016

The Solder Excursion Diversion

Amy is shocked at a revelation from Sheldon after she buys him a new laptop. Also, Koothrappali sells out Leonard and Wolowitz after they lie to their wives in order to attend an early screening of a movie.

The Big Bear Precipitation

Episode: 9x20 | Airdate: Apr 7, 2016

The Big Bear Precipitation

Sheldon spills a secret of Leonard's when the two take a weekend cabin trip with Penny and Amy. Also, when Koothrappali goes overboard with pregnancy gifts, Wolowitz and Bernadette must draw the line.

The Viewing Party Combustion

Episode: 9x21 | Airdate: Apr 21, 2016

The Viewing Party Combustion

Everyone must choose sides when a small argument between Leonard and Sheldon erupts into a heated fight during a group get-together.

The Fermentation Bifurcation

Episode: 9x22 | Airdate: Apr 28, 2016

The Fermentation Bifurcation

The gang goes to a wine bar and runs into Penny's old boyfriend, Zack. Also, Bernadette gets stuck spending the evening with Sheldon when she can't go wine tasting with the group, and things don't go as planned when Koothrappali introduces his new girlfriend, Claire.

The Line Substitution Solution

Episode: 9x23 | Airdate: May 5, 2016

The Line Substitution Solution

Sheldon hires Stuart to spend the day with Amy when he'd rather go to a movie screening. Also, Leonard's mother, Beverly, comes to town and Penny struggles to make a connection with her.

The Convergence Convergence

Episode: 9x24 | Airdate: May 12, 2016

The Convergence Convergence

Chaos ensues when Leonard's recently divorced parents, Alfred and Beverly, and Sheldon's devoutly religious mother, Mary, come to town. Also, Wolowitz and Koothrappali think the government is out to get them when they are contacted about their guidance system.

Season 10

The Conjugal Conjecture

Episode: 10x01 | Airdate: Sep 19, 2016

The Conjugal Conjecture

After Sheldon's mother and Leonard's father share an evening together, everyone deals with an awkward morning the following day. Also, Penny's family arrives for the ceremony, including her anxiety-ridden mother, Susan, and her drug dealing brother, Randall.

The Military Miniaturization

Episode: 10x02 | Airdate: Sep 26, 2016

The Military Miniaturization

Colonel Williams, an Air Force representative from the Department of Material Command sits down to talk with Wolowitz.

The Dependence Transcendence

Episode: 10x03 | Airdate: Oct 3, 2016

The Dependence Transcendence

Tensions rise when the boys struggle to complete their government project on time and Sheldon tries an energy drink to stay awake. Also, Penny and Amy go to a "party" at Bert the geologist's house, and Kooothrappali learns Bernadette's true feelings about her pregnancy when they clean out the future baby room.

The Cohabitation Experimentation

Episode: 10x04 | Airdate: Oct 10, 2016

The Cohabitation Experimentation

When Amy's apartment floods, she proposes a "cohabitation experiment" with Sheldon. Also, Howard and Bernadette are upset when Koothrappali learns the gender of the baby before they do.

The Hot Tub Contamination

Episode: 10x05 | Airdate: Oct 17, 2016

The Hot Tub Contamination

Leonard and Penny must separate a quarreling Sheldon and Amy when their cohabitation does not go as planned, and Sheldon threatens to break off their relationship when Amy refuses to adhere to the bathroom schedule. Also, Howard and Bernadette find unexpected guests at their house when they decide to stay home from a planned vacation.

The Fetal Kick Catalyst

Episode: 10x06 | Airdate: Oct 27, 2016

The Fetal Kick Catalyst

Penny is surprised to learn she has fans of her performance in "Serial Ape-ist" when she attends Van Nuys Comic Con with Leonard. Also, Amy hosts a Sheldon-style brunch at Penny's apartment, and Wolowitz makes an impulsive purchase when he starts stressing out about the baby on the way.

The Veracity Elasticity

Episode: 10x07 | Airdate: Nov 3, 2016

The Veracity Elasticity

In order to continue living with Sheldon, Amy lies to him about repairs being made to her apartment and they host an "on location" episode of "Fun With Flags" in Penny's apartment. Also, Leonard lets Penny decorate Sheldon's old room after he learns that she has been secretly moving Leonard's collectibles into storage.

The Brain Bowl Incubation

Episode: 10x08 | Airdate: Nov 10, 2016

The Brain Bowl Incubation

After a successful experiment combining their genes, Sheldon will stop at nothing to convince Amy they should procreate. Also, Koothrappali is embarrassed to tell the gang what the new woman he's dating does for a living.

The Geology Elevation

Episode: 10x09 | Airdate: Nov 17, 2016

The Geology Elevation

When Bert, a Caltech geologist, wins the MacArthur Genius fellowship, Sheldon is overcome with jealousy. Also, Wolowitz finds an old remote control Stephen Hawking action figure he invented.

The Property Division Collision

Episode: 10x10 | Airdate: Dec 1, 2016

The Property Division Collision

Sheldon and Leonard must divide up their possessions and remove Penny's things from 4B.

The Birthday Synchronicity

Episode: 10x11 | Airdate: Dec 15, 2016

The Birthday Synchronicity

Sheldon and Amy attempt to have an intimate moment together to celebrate Amy's birthday; Bernadette and Wolowitz welcome their newborn baby to the world.

The Holiday Summation

Episode: 10x12 | Airdate: Jan 5, 2017

The Holiday Summation

Sheldon and Amy visit Leonard and Penny for the first time since the holidays and share details about their terrible trip to Texas.

The Romance Recalibration

Episode: 10x13 | Airdate: Jan 19, 2017

The Romance Recalibration

Leonard and Penny ask for Sheldon's and Amy's help on putting the romance back in their marriage. Howard and Raj go to extreme lengths to stop the floor in Halley's bedroom from making noise.

The Emotion Detection Automation

Episode: 10x14 | Airdate: Feb 2, 2017

The Emotion Detection Automation

Sheldon beta tests an MIT invention after hearing it can help him read people's emotions. Also, Leonard can't hide his feelings when Penny announces her brother is coming to town and Raj invites his ex-girlfriends over to give him dating advice.

The Locomotion Reverberation

Episode: 10x15 | Airdate: Feb 9, 2017

The Locomotion Reverberation

Leonard and Wolowitz try to distract Sheldon when he slows the progress of their guidance system. Also, Penny and Amy take Bernadette out for the night, leaving Raj and Stuart to care for baby Halley.

The Allowance Evaporation

Episode: 10x16 | Airdate: Feb 16, 2017

The Allowance Evaporation

Sheldon and Amy have their first fight since moving in together, and Koothrappali is shocked at the realities of financial independence when he stops receiving support from his father.

The Comic-Con Conundrum

Episode: 10x17 | Airdate: Feb 23, 2017

The Comic-Con Conundrum

With Koothrappali cut off from his father's fortune, he appoints Sheldon to help him get out of debt. Also, Penny considers joining Leonard at Comic-Con.

The Escape Hatch Identification

Episode: 10x18 | Airdate: Mar 9, 2017

The Escape Hatch Identification

When Raj moves out of his apartment, Leonard and Penny offer him Sheldon's old room.

The Collaboration Fluctuation

Episode: 10x19 | Airdate: Mar 30, 2017

The Collaboration Fluctuation

Leonard, Penny and Raj adjust to their new living arrangement, and Sheldon takes an interest in Amy's work.

The Recollection Dissipation

Episode: 10x20 | Airdate: Apr 6, 2017

The Recollection Dissipation

Sheldon pushes himself to the limit when he collaborates on projects with Leonard and Wolowitz as well as Amy on the same day. Also, Bernadette is nearing the end of her maternity leave and must return to work.

The Separation Agitation

Episode: 10x21 | Airdate: Apr 13, 2017

The Separation Agitation

Howard and Bernadette have a hard time leaving Halley in day care when Bernadette returns to work. Also, Bert introduces the gang to his new girlfriend, Rebecca.

The Cognition Regeneration

Episode: 10x22 | Airdate: Apr 27, 2017

The Cognition Regeneration

Leonard isn't thrilled when Penny considers taking a new job offered by her ex-boyfriend, Zack.

The Gyroscopic Collapse

Episode: 10x23 | Airdate: May 4, 2017

The Gyroscopic Collapse

After Leonard, Sheldon and Wolowitz celebrate the completion of the top secret air force project, they are met with an unpleasant surprise. Also, Amy is offered a summer position as a visiting researcher.

The Long Distance Dissonance

Episode: 10x24 | Airdate: May 11, 2017

The Long Distance Dissonance

The gang is concerned when Sheldon's former admirer, Dr. Ramona Nowitzki, resurfaces while Amy is away at Princeton.

The episode guide was truncated because of the large number of episodes. Click here to show them all.