A famous but old game. I am not sure if many people play it anymore but apparently there are decent bots to play with, and bots don't exhibit anti-social behaviour like griefing and team killing.
Steam Daily Deal - 75% off Counter-Strike: Condition Zero (Now $2.50 US)
90
:) alot of memories with this game, still has a small community was playing it up till about year and half ago when i finally desided to stop playing "got in 2 lol", jumped back in about 3 weeks ago and had couple games still fun
worth the money
btw it also has a single player campaign of sorts so its worth getting it for those missions alone