There is a bonus zombie mode you can unlock in Call of Duty: Black Ops for the PS3, Xbox 360, and PC called Presidential Zombie Mode.
You can unlock Presidential Zombie Mode two different ways. You can either beat the game on any difficulty, or you can enter a cheat code on the computer in the main menu.
To access the computer on the main menu, you need to mash the aim and shoot buttons (on PC, just mash the spacebar) until you break free of your restraints. Once you break free, walk up to one of the computers behind you and type in 3ARC UNLOCK to unlock both Presidential Zombie Mode and Dead Ops Arcade.
When you do this, you’ll see a new map in Zombie mode called Five, which is what is referred to as Presidential Zombie Mode.
