Very cool stuff, this is one sport I could be good at ! :)
Now picture this, a real skeleton racer for the summer olympics, as a kid we built these skeleton racers with 4 steel ball bearing wheels, two planks nailed together in a T, and a front axle bolted to the front, a knee pad at the back, two little knobs on the front axle for steering. We would take these ball-racers up the storm water drains where we lived, and race them down - talk about an extreme sport, head first down a dark tunnel, no helmet or protective gear - wheeeeee :p