Excessive Unreal 2 is one of the most chaotic, stupid, hilarious, and insane mods ever made for Unreal Tournament, and it has incredibly well-balanced, action-packed gameplay. If you like Serious Sam, Doom, and Unreal - especially when blended together in the most absurd (yet somehow perfect) way - this mod is for you.
Latest version as of January 24, 2013. This will bring a v5.02 install up to v5.03. If you have an earlier version, get v5.03 FULL instead, or download earlier patches (available on the EXU2 Forums).