This weekend, and presumably this weekend only, D.O.A. (Dead Ops Arcade), and Five (The second zombie map that you need to beat Black Ops to open) are being unlocked for you so you can play them all this weekend. They are only being unlocked for the PC, Playstation 3, and Xbox 360 users.
Dead Ops Arcade is a Super Smash TV style top down 4 player co-op madness crazy action awesome bonus game for Black Ops. And Five is an amazing zombie map that takes place inside the Pentagon. Playable characters include John F. Kennedy, Robert McNamara, Fidel Castro and Richard Nixon. You can’t go wrong with that cast of characters, trust me.