mate showed me this last night
While sitting in the chair at the main menu press LT, RT, LT, RT, LT, RT, continuously until you break free from your wrist straps. Now walk around the back of the bank of monitors to the computer terminal and enter the code '' 3arc unlock '' (without the ''s)
when you go to Zombie Mode you will notice the “Five” Zombie map will be unlocked!!
To unlock Black ops arcade mode do the same as above but enter ''DOA'' (without the ''s)