The Wikipedia link above explains what Rube Goldberg machines are.
Excerpt, which gives a definition:
[ A Rube Goldberg machine , contraption, invention, device, or apparatus is a deliberately over-engineered or overdone machine that
performs a very simple task in a very complex fashion, usually including a chain reaction . The expression is named after American cartoonist
and inventor Rube Goldberg (1883–1970).
Over the years, the expression has expanded to mean any confusing or complicated system. ]
I really like the first machine example (with a diagram) - the self-operating napkin. See link above.
The article says that there is a Rube Goldberg Machine Contest held regularly :-)
As a teenager, I once invented an automatic fish-catching device :-) It was a fishing rod with modifications. I guess it could be considered as a sort of Rube Goldberg machine, though I didn't design it with that goal in mind, and it also had less parts than the typical RG machine.
Update: the Wikipedia article has many links to, or descriptions of, Rube Goldberg machines, including, surprisingly, a Tamil movie in which the hero, Kamalahasan (a top star in south India), kills the villain using a Rube Goldberg machine! :-)
- Vasudev Ram