When Archimedes thought up his revolutionary water-pumping screw, little did he know that one day a group of high school students in Lyon, France, would find a better use for his design. Their Propul-Surf uses a pair of horizontally-mounted screws to push a snowboard through the snow when gravity doesn't provide enough momentum.
The rig, which is powered by a pair of motors borrowed from an electric bicycle, is designed to be easily removed when a snowboarder gets to the top of the hill so they can let gravity take over again. Not surprisingly, the Propul-Surf doesn't provide anywhere near the speed and thrills as you'd get from something like a snowmobile. But compared to slowly hiking back up a hill with your board in tow, it might as well be an amusement park thrill ride.