It's a stand alone expansion (so you don't need the original game to play it, it's a full game on it's own) to the new Wolfenstien game (it's name escapes me). You can download it from the internet for free. I installed it, but it doesn't have a 1 player game and i'm not big on playing with strangers. Has anyone else tried it?
Wolfenstien: Enemy Territories
Yeah, Its multiplayer only, and it kicks ass, I recommend it to those who like team based multiplayer games.