Last winter my wife and I took our daughter sledding at a nearby hill. There were a bunch of other kids and parents with, as usual, a variety of things used to ride on.

One of the fastest "sleds" was a mildly curved fibreglass oval, just the right size for an adult or a couple of kids to sit on. It was a Futuro window, from the factory that made them! More precisely, I think it was part of a mold for a window, since the inner surface was pretty rough, and as I said it was fibreglass. So while the Futuro never took off as a ski lodge, or otherwise, it's at least good for getting downhill in a hurry.