Well you did say "like" free which means I'm gonna suggest cheap I still play Command and Conquer Renegade more than any other game. You could run that game on max with that system and the multiplayer on that game is AWESOME. My friend only paid $10 for the old command and conquer pack that came with Command and Conquer red alert and expansions, red alert 2 and Yuri's Revenge, and Renegade.
And wouldn't a older version of America's Army run on that system to?