S4·E20 Operation: C.O.U.C.H.

Numbuhs 1, 2 and 5 all go off to China after Numbuh 4 falsely alerts them of trouble there. He then watches TV in their absence, but Numbuh 3 doesn't leave, either, and they fight over the remote control, which falls into the couch. Numbuh 4 goes into the couch after it... and winds up a strange world where everyone is named Dave, who want the control for themselves.