S11, E18: Lyndsey discovers that Alan is sleeping with Larry's sister, Gretchen. Meanwhile, Walden struggles with telling Barry (guest star CLARK DUKE) to find his own place.

Starring Clark Duke, D.B. Sweeney, Courtney Thorne-Smith
S11, E18: Lyndsey discovers that Alan is sleeping with Larry's sister, Gretchen. Meanwhile, Walden struggles with telling Barry (guest star CLARK DUKE) to find his own place.