The latest Call of Duty: Black Ops is out and people have started to unlock secrets in the game already. and as it turns out the developers have put in two mini games in the game too. First one is "Dead Ops Arcade" which is a top down shooter using CoD:BO zombie resources. the other is the classic text adventure game "Zork", which activision own the rights of. To unlock this on menu screen, when you are tied to seat you have to break free and get away from game standard menu and go to computer in back running dos and then just type "DOA" or "ZORK" to play respective game. following video demonstrates this on X360, same is applicable on PC and PS3:
Source: JDL