For the uninitiated, a Rube Goldberg machine is a device that is designed to do something relatively simple in a very (very) complicated way.
One of the best Rube Goldberg machines I have ever seen is featured in this OK Go video. (OK Go is renowned for making really challenging and interesting videos. If you haven’t seen them, I highly recommend it.)
(Posted today as my Day 18 entry in the Blogging from A to Z Challenge)