Jimmy Fallon was courteous enough to walk his guest Stephen Colbert out of the building last night, but the pleasantries didn't last long. Neither did the ensuing aggression, though. On his own show, Stephen Colbert tested Jonathan Safran Foer's vegetarianism with a plate of "flacid" bacon (Foer's word). Finally, David Letterman and Jay Leno responded to their Super Bowl ad on their respective shows. Watch our compilation to see what you missed.