Awsome tactical FPS made by the U.S. Army.
Easily the best free game available today, America's Army is based on realism. Despite cries of, "propaganda, propaganda!" (see stupidly long definition at he bottom of the page). Most AA players are in it for fun.... and this it delivers effectively.
It is easy to die in AA, ususally 3 or fewer hits is enough to end your game, and once you're dead, you dont come back until the next round. This forces players to play with their brain and work as a team, much like the real army must do to stay alive in the field.
Weapons are modelled realisticly in looks, sound, and the way they behave. The gunshots are actually recorded from the shooting range, and the reloading animations are accurate to a T.
The most interesting feature of America's Army is the way the teams are set up; there is no "terroists versus U.S.". Instead both teams see themselves and their teammates as US soldiers with US weapons. And will see the enemy as Terrorists with Russian made firearms. The oppsing team will see the exact opposite.
America's Army's graphics are nothing special, but there are no major complaints, as long as you have decent graphics hardware.
"You guys up for Some Amerca's Army tonight?"
"HUA! I just finished downloading America's Army"