In Call of Duty: Black Ops, How to Get Other Zombie Maps
This tutorial will show you how to unlock the two other maps for Zombies on Call of Duty: Black Ops.
Step 1: Go to the main menu
Step 2: Look down at your hands and press LT, and RT at the same time (You may need to do this a few times)
Step 3: You character should have gotten up from the chair. If so, you should walk to the back of the room and press X when prompted by the computer.
Step 4: Enter the code 3Arc_Unlock into the computer.
Congratulations! You now have the maps!