The Cheat Code section for the Call of Duty Black Ops Strategy Guide will give players a walkthrough of some elements in the game that aren't so in your face.

Directions:At title screen, use the analog sticks to look down at your hands that are strapped into the chair. Press RT + LT or (L2 + R2) to escape from the chair. This will unlock the "Just Ask Me Nicely" achievement/trophy. After breaking out of the chair walk around behind the chair and find the old computer. Use the computer to enter the following codes.

3arc Unlock: This code unlocks the "Five" Zombie mode mission, Dead Ops Arcade game, Zork text based adventure game, and all missions

3arc Intel: This code unlocks all Intel. WARNING Enabling this code prevents you from getting the "Closer Analysis" achievement/trophy.

DOA: This code unlocks the Dead Ops Arcade game which is a mini-game over top camera view. This game is how you unlock the "Insert Coin" achievement/trophy

ZORK: This code unlocks the Zork text-based adventure game. Play this game in order to unlock the "Eaten By A Grue" achievement/trophy.

help: This code will display a list of commands in the terminal and Pentagon user email access.

Secret Codes Video Walkthrough
http://www.youtube.com/n66BUxzhgic