Halo 3 Easter Egg - Real Hidden Terminal

On the level Cortana, there is a hidden terminal near the Tilt Skull. To get there, progress through the level as normal until you get to a room where Cortana mentions playing games. Then wipe out the Flood (trust me, it makes things a LOT easier) and go into the room at the bottom. Look around for a Grav Hammer resting on a pillar. This pillar is actually a terminal, and when accessed, will give you a message from Cortana.