For as long as Americans of the Northern climes have had a moment for leisure during the winter months, Americans have taken to sledding. Whether on a raised wooden platform with cast-iron runners, or on a simple piece of cardboard, or on a tray stolen from the college cafeteria, kids of all ages recall fond memories of racing down hill, of the sting of a biting wind in their faces, and of the numbness of cold hands and toes.