Don't let that awesome "Tonight, Tonight" duet fool you — Jay Leno is still pissed at NBC, and possibly because April Fool's Day brings about fun abandon, Jon Stewart, Stephen Colbert, and Jimmy Kimmel joined the network beat-down last night. Leno opened his monologue with "NBC and I have reached a peaceful, amicable agreement that is both beneficial to both sides ... (pause) ... April Fools! That's totally ridiculous! Never happened!" Watch the rest of the NBC disses straight ahead.