Sign on Zanzibar
On the beach on Zanzibar, you will see signs that say NO SWIMMING. Well, go to your xbox dashboard, go to the Settings, Clock, and change every number you can to 7 , then pop Halo 2 back into your xbox and load it up. WARNING: Do not sign into XBoxLive, it resets your clock. Now go to Split-Screen and start a game on Zanzibar. Go to the beach and look at the sign, it will mention something is missing, and there is a bloody dog's head.