Call of Duty: Black Ops has a great Easter egg on the main menu which allows you shoot and kill tons of Nazi zombies! And it's really easy to find. Basically, from the main menu, look down at your restraints and start tapping LT and RT to break free. This will give you the "Just Ask Me Nicely" achievement. Next, go to the computer and type in DOA, which will unlock Dead Ops Arcade. When you start playing the game, you'll earn the "Insert Coin" achievement. That's it!
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