I meant to post this the other day and it slipped my mind, so better late than never. Measels created a thread in the Halo 1 trick section, showing off a short video created by a whole team of guys on Halo PC. They manage to stack and then bump through the top ledge of Hang Em High and then walk around on the space above the level, on a barrier that apparently doesn't exist on Halo for the Xbox (or so I hear). At any rate, fun video - check it out.