Massive Action Game
I think is what it stands for, basically supports huge FPS fun 128 vs. 128 with squads, team leaders, squad leaders, various weapons you can upgrade, skills you can buy with things you earn, vehicles (like tanks), jumping out of planes over an enemy position, etc, etc, etc.
PS3 only though, but when you pre-order it from play.com you get a beta invite, and I got mine the day after I pre-ordered.
Only down side is the times the server is up as it's a beta is limited, but the times I do get to play I've had a blast, even if I only seem to do well as a sniper, as a grunt I always seem to be one of the first to die, but respawn isn't a long wait and you can change your weapon loadout while waiting so you can keep busy, but respawn is done in waves so if you are faffing around with weapons and you miss the respawn, you need to wait for the next one (happened a couple of times for me but I didn't mind as I was getting used to the UI and weapon choices)