Cleverly dubbed 'The Secret War'
Well this one snuck up on me - a prologue game to set up the story of The Secret World has launched, dubbed The Secret War. All sorts of goodies are open to you if you play, including access to the game, in-game items, and even a trip to visit the developers. The announcement is in the first link, but what you really want is the game, in the second link. Go nuts!