Unreal Tournament 2004
Botworld is a single player mod, that increases the number of bots to 499. You get 2 new ladder modes- 1v1 and FFA, with each having 500 competitors (499 bots plus the player). Each bot has their own profile page that is more extensive than the original UT2004 ones. The bots' AI is the same as in UT2004, but now you don't need to choose between difficulty settings- individual bots range from the worst setting to the best setting possible (i.e. some bots are much better than others).
Botworld - a mod for UT2004 by Ben Greenwood.