Cast Credits Girls (2012) Guest starring as Dave Groban Episode 4x06: Close Up (Feb 22, 2015) FlashForward (2009) Guest starring as Professor Corey Episode 1x18: Goodbye Yellow Brick Road (Apr 29, 2010) Numb3rs (2005) Guest starring as Victor Stokes Episode 6x04: Where Credit's Due (Oct 16, 2009) L.A. Law (1986) Guest starring as Charles Knotts Episode 3x08: I'm in the Nude for Love (Jan 12, 1989) The Golden Girls (1985) Guest starring as Dan Cummings Episode 4x22: Sophia's Choice (Apr 15, 1989)