An o-shibori (hot towel) service. They're common in Japanese restaurants, and when I visited Tokyo in the middle of summer, I looked forward to the hot towel al

An o-shibori (hot towel) service. They're common in Japanese restaurants, and when I visited Tokyo in the middle of summer, I looked forward to the hot towel almost as much as the meal. You could resell or lease the equipment and provide daily laundry / sterilization service.