http://www.worldinconflict.com/beta/
A really good RTS game with a multiplayer open beta. You can play the tutorial and a 2-16 player match in the beta. You get 2 maps to play on, or if you preorder it you get a bonus third. The storyline is if the cold war actually ignited and didn't end in 1989. Play as either the americans or soviets. Really good RTS game, seriously go to the site and get a beta serial key before they are all gone... very limited quantities!