DAVE Easter egg
From Halopedia, the Halo wiki
The DAVE easter egg is an easter egg found in Halo: Reach.[1]
Description
The easter egg can be found on the Mark V BIOS in any gametype. When a non-scoped weapon is zoomed-in, a line of binary code is visible in the lower-left corner. The numbers read 01000100011000010111011001100101. When translated from ASCII eight-bit binary code, the code reads "Dave", a reference to Bungie interface designer Dave Candland.
Trivia
The same binary code can be seen in the same place in the Halo 3 Beta.
Sources