Here is an interesting comparison of Cortana over the course of the 4 halo games:
PTesh adds his dulcet prepubescent tones over the top of one of the new trailers for weapons...
Try upgrading your browser to Google chrome (you wont regret it). There is probably an IE...
Da Vinci Code Egg
Spawn in sandtrap with an invulnerable shield. Be in forge to if you want to. But go to the invisable barrier and walk back and forth into it then end the game ok. Then go to theater mode put the camera at the barrier were you walked into it. Walk into camera until your body pushs the camera thru the barrier. Try a couple times until the camera goes thru the barrier. Then fly to one of the towers lining up around the level that have lights on it. at the top of each tower there will be an easter egg with letters and will be blue. But be carefull they're very small. Good Luck with it.