The flying Tank! lolololololol!
Alright, here's what you do. Go on to Forge mode on the map: Last Resort.
Then, spawn a tank near the spinning wheel. Get inside of it, and get in the path of it going up, start moving forward and when you hit the little edge halfway there, you will go flying into the air while spinning.
P.S. This worked better on Halo 2, but at least they didn't fix the glitch!
Theres loads more info this game, right here, with some cheats and tips, answers and Halo 3 walkthrough.
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