Black Ops Zork and Dead on Arrival Easter egg

Ok I just got showed this by my brother. Anyway what you do is on the main menu, you look down at your hands and click R,L,R,L,R,L,R,L and continue until your hands come free, then walk around the room and look for a computer. Write Zork or DOA. then you can play Zork a typing game with adventure in your mind or you can write DOA then you can play sort of like GTA 1 but you have to kill zombies hope this helps you guys for when you get the game I will try to find the link and then I will edit the post