Physics Remastered
From the Physics Remastered team (with some help from grumpy):

Halo 3 has been remastered by a team of tricksters called, what else, Physics Remastered. These beautiful vids are done old-skool HIH, meaning we took the time to include tutorials in each vid.

The Island
An area that was thought to be impossible to reach, has been fully explored by L337 PWN4GE and SlowhandHendrix. The video includes a tour of the area, an in-depth tutorial and some sweet techno music. Oh and please visit our thread here!

The Fog Room
While exploring the possibilities of load zones, a mysterious foggy room was been discovered by a few members of Physics Remastered. Two days later, the bottom was touched and the whole area was explored. Check out the video by clicking the link above.You can see our thread right here!

The Fence Ceiling
An area, that was a personal challenge we set for ourselves, was explored by Physics Remastered. This is one of the few areas that can only be reached by standing in an area where two parts of the map overlap.It was amazingly fun to do. You can discuss The Fence Ceiling here!

FP, cool, it's worth a watch because the tuts make all the difference for the great tricks.

Also; I'm glad marioman769 rewrote my sugestion, I didn't want to interfere but I did want the vids to make FP. I just wasn't sure if the writeup by L337PWN4GE would be too long so I'm happy it all worked out. Looking forward to more flicks from you guys at Physics Remastered.
I highly recommend all of these videos. Good show, PR ^_^