Just in case you haven't heard of these, there are a couple of hidden game modes. I just watched someone playing Dead Ops.
Call of Duty: Black Ops: How to Unlock Dead Ops Arcade and Zork Mode
November 09, 2010
Hidden within the main menu of Call of Duty: Black Ops on Xbox 360, PS3 and the PC are a pair of neat little Easter Egg games waiting to be found. The first is Dead Ops Arcade which plays just like it sounds. The second, Zork, is a text-based game.
Both of these games are accessed by using the Right Analog stick at the main menu to look down. You'll notice your character's wrists are tied to a chair. To escape the binds, press the Left and Right Triggers repeatedly until you break free.
Once free, move around the area to the right and locate a small computer terminal against the wall. Follow the prompt to use the terminal and then type DOA to fire up Dead Ops Mode. You can also type ZORK to play that mode, or even 3arc Unlock for these unlockables: Zork mode, Dead Ops Arcade mode, the 'Five' Zombie mode map and all the missions. More useful commands at this terminal can be found by entering help at the prompt.
For those trophy hunters out there- (Martin, Death
) there's 3 easy trophies for you right there.