The Leidenfrost Maze

The Leidenfrost effect is a phenomenon in which a liquid, in near contact with a mass significantly hotter than the liquid's boiling point, produces an insulating vapor layer which keeps that liquid from boiling rapidly.
The Leidenfrost Maze was designed and built by University of Bath undergraduate students Carmen Cheng and Matthew Guy to demonstrate the self-propulsion of Leidenfrost droplets at public outreach events and schools.

YouTube link
(via Miss Cellania)