Before anyone is all "OMG THAT MC COSTUME IS AWESOME!"... That's not a costume, it's a life-sized STATUE of the Chief (Halo 3 version). So yeah, I got a pic beside him as Cortana.
No hooker-tana unfortunately, I didn't feel like breaking an ankle at Halofest.
Sorry for the bad lighting, my camera sucks and it was decently dark in there.
Taken at HaloFest at PAX Prime 2011
Cortana made by me
Picture taken by whoever had my camera at the time