Flying trash can

The Flying Trash Can can be seen on the level The Storm in Halo 3. You can see it when you go to the part where the Mongooses are with the Marines that have Rocket Launchers. This must be done with at least two or three players to help you. The trash can is right outside of the door of the Mongooses. Instead of going down the ramp there is the path next to the ramp and there you will see the trash can.

How to do the Glitch
First tip the trash can on it's back with a grenade or rocket. If done properly the top door should be laying bare open on the ground so you can walk into the exposed can. Next two of you crouch and walk into opposite corners of the trash can. Look straight down and continue walking until you both see the ground on the other and adjacent side through the trash can. Then start jumping and don't stop jumping when you see your legs stop moving, as this means you are in the glitch. You can turn your head around in order to see where you are going, so long as you do not stop jumping.