Back in 2010 I came across The Ultimate Machine, a machine that has one function: to turn itself off. A user flips a switch to turn the machine on, the machine promptly reaches out and flips the switch off -- rinse and repeat. Things got a little more out of hand in 2011 with an Ultimate Ultimate Machine that added a kinetic component.
Two years later, here's yet another Ultimate Machine, with a serious attitude. My favorite part comes at 0:52.