Holy hell does this game rock. It's available for the PS2 and XBox, and it's cheap now. N64 GoldenEye level of multiplayer awesomeness, funny as hell, and the XBox version has a beautiful 480p implementation. Overall a great looking, smooth playing, ridicilously funny game with HUGE multiplayer options.

Also, there's great fun to be had in playing multiplayer against: A buxom female raver, a ninja monkey, a 60's secret agent named "Harry Tipper", and a scythe handed zombie with a deer's head called the "Deerhaunter".