Agree with Swat 4, except we always end up tasering each other and not the enemy. Also the occasional point blank shotgun to the face of a restrained terrorist. But hey its our lan so we can do these things eh?

Our fav games that have survived test of time:

Ravenshield + Mods - had some seriously fun times, especially as co-op

Quake 3 - the demo is 50 megs and runs on any OS and has bots. Great way to get the lan started and work out nettwork etc without long setup time.

Starcraft- this is probably recognised as the best RTS ever and is cheap

CS: Source - not my fav by the way

Other good ones - UT2004(bots and mods galore)

COH - awesome game but the other guys aren't really into it

If you like flying IL2 and Lock-on are incredible if played seriously in co-op