Until today I had never heard of Rube Goldberg. I had seen some of his comic illustrations but certainly never heard of the concept of "a Rube Goldberg machine".
Read about him and the machines here at Wikipedia and visit "the Official Rube Goldberg Web Site". Below you can watch a couple of videos of Rube Goldberg machines (via Milk and Cookies).
If you feel inspired maybe you'd like to play this game.