Forge is a game, released last year, that was a product of Steam's Greenlight program. It's an online, team-based game with classes, and it's quite good. It's being re-released as a more "fleshed out" offering AND will be 75% off on Steam, making it only $5 for a limited time. If you've got an extra $5 (and a Steam account), it would be worth checking out.
http://massively.joystiq.com/2013/04/24/forge-rerelease-introduces-tons-of-new-features-75-off-on-stea/