Black Ops hides Zork easter egg

Players have been discovering a secret in the game call of duty black ops, following these steps and you can discover it too! first, break away from the main menu and find a computer running on DOS and type in "zork" and you'll play the classic infocom text adventure. You will also get the "eaten by a Grue" achievement. You may also access a tap-down zombie shooter called Dead Ops Arcade by typing "DOA" into the computer.