Watch the Halloween episode of That 70s Show!

Watch carefully when Eric hangs on to the gutter.

Then watch Fez "fall" off the roof.

I believe Eric is laying down on the floor grabbing the gutter with the "ground" up on a wall behind him. The camera angle looks like they are looking down. Then, Fez falls and he just walking backwards...then *boom* he hits the "ground" aka wall and isn't even leaning all the way up against it!