ON The main menu of Halo with the huge Halo 2 logo.

Just underneath there is a message written on the main Menu font, but you can only see the bottom half of the word. And there are no spaces. But the Message goes something like:-

"David Candland is the greatest designer to live in the 21st century, his work is astounding and he is very humble"

David Candland is the Menu Designer for Bungie, so i guess that's his contribution to the system.

There is also a billboard above a building which reads, "Tterrab Industries" Trerrab is Barrett backwards. (duh!) Christopher Barrett is also one of the Bungie team.

Have fun!