If you've never played a team-based war game before, War Rock could be your gateway drug. Join a team, pick a class (scout, engineer, medic, combat, or heavy weapons trooper) and jump head first into an all-out war with up to 63 other players.
It's a poor man's Battlefield 2, to be sure, but its lack of top-notch graphics and polish is offset greatly by the fact that it's one hundred percent free to download and play. Between that and it's relatively modest system requirements, War Rock could amass a huge following very quickly.
When you fire up the game, you are presented with three options: close-quarters combat mode, designed to emulate Counter-Strike's claustrophobic maps (complete with bombing missions); urban combat mode with maps big enough for light vehicles to roam and some nice spots for snipes to nest, where players attempt to capture and hold bases around the map, Battlefield style; and long-range combat mode with giant maps that include tanks, jets, helicopters, and more. In keeping with the philosophy of accessibility, vehicles are all easy to jump in and get the hang of right away, even the notoriously difficult helicopter.
While the game is free and allows players to earn new equipment through wracking up points, you have the option to pump some real world cash into the game to buy in-game currency. Paid players also get a few perks when it comes to hosting games, but nothing that will make the game less fun for everyone else.