I know I've played in funny games. I know I've run some games where funny stuff happened. But I'll be damned if I can remember a single game that was the funniest of them all.
There was one time, I was running Edge of the Empire for the first time. I used the beginner box adventure, but the players had drawn up their own characters. At the end, they've stolen (acquired?) a Trandoshan slaver's ship and they're flying away into space. Someone asked if there was any food on board. The conversation went something like this:
GM: There's several chunks of raw meat in the refrigeration unit.
Player: What kind of meat is it?
GM: You have no idea. For all you know, it's Wookiee meat.
Player: I cook some up. How is it?
GM: It's a little Chewie.
Yeah, rim shot. We laughed about that one, given the spontaneity of it. There were a few other Wookiee-themed cracks, too, but that's the one I remember the most.