I have friends who are double-jointed. They can do freaky things with their arms and fingers...but nothing like what I witnessed in this video. This kid literally spins his head 180-DEGREES! I watched it a few times and can't tell if there's some sort of trickery going on.
I was starting have my doubts about the validity of the whole thing when I came across this other video. If there's an "edit"...I certainly can't see it.