Call of Duty: Black Ops has realistic warfare, zombie shooting and a secret Pentagon defense mode that has you shooting zombies as President Nixon. Then it has this - a top-down arcade shooter mini game called Dead Ops Arcade.
But accessing it isn't just a matter of finishing the game. You've got to bust your way out of the main menu screen, then work your way around to a terminal and type in the correct commands to boot the game.
While in the menu look down (using the right analogue stick, presumably) at your hands and mash the triggers to wriggle your hands until they come free.
You'll stand up and be given the freedom to roam. Go to the terminal, access it and enter CD, then DOA. Bam - giant machine guns, flame throwers and rocket-firing bats are yours for the shooting.
There was a video on Youtube but Activision took it down.
