Fun multiplayer recommendations?

I'm looking for some fun, multi-player games that don't revolve around a sport or racing, any suggestions? They can be cool shooters or insane party games, whatever ..

There ar elots of them, I can reccomend  two games that are fun when you playc with someone else:

Timesplitters 2 great offline multiplayer

ratchet deadlocked, great online multiplayer.(if you get this we can play online ^^) 

Theres alot of games with great online ill name a few

timesplitters series

star wars battlefront 2

soul calibur

ratchet and clank deadlocked

mortal kombat armagegaddon

and much much much much much more

Mortal Kombat Shaolin Monks

Burnout Revenge