The most recent film I've seen where I nearly wet myself was Knocked Up. The best scene for me was at the circus in Vegas and they're tripping on
shrooms.
"No! Don't clap! You'll make him fall!!!"
Man, I laughed so loud at that.
Also, when they're in the hotel room and that guy (can't remember his name) is loving the chairs, and then he gets "dark vibes" from one of them!