In this 2013 video by Science Friday, researchers take advantage of the Leidenfrost effect to make droplets of water flow up an incline. The Leidenfrost effect occurs when a liquid is placed on a surface that is significantly hotter than the liquid’s boiling point. A layer of vapor prevents the liquid from touching the surface and thus boiling rapidly away—the vapor also allows the liquid to move across the surface with ease.
via The Awesomer