I found a nifty little mod yesterday called Occupation. It's basically a very heavily altered game of Counter Strike Source with iron sights, ammunition types, a full biometric simulation of every fragmentation from every damn bullet fired from every damn gun, and other stuff. I'll be hosting it non-dedicated for the next... I dunno, 2 hours, so come on over and check it out.
You'll need Half-Life 2, CS:S and both the game and 1.2.1 patch installed to play. It's free.
Download is
here and
here for the patch.