(For those not entirely familiar with it, the "Many-worlds interpretation" is a view where every random event causes a new universe to split off — see the "parallel universes" so beloved by cheesy sci-fi.)
"One good example of this is the Quantum Suicide "experiment" that some proponents of the Many-Worlds Interpretation claim (I think jokingly) could actually be used to test the MWI. The way it works is, you basically run the Schrödinger's Cat thought experiment on yourself– you set up an apparatus whereby an atom has a 50% chance of decaying each second, and there's a detector which waits for the atom to decay. When the detector goes off, it triggers a gun, which shoots you in the head and kills you. So all you have to do is set up this experiment, and sit in front of it for awhile. If after sixty seconds you find you are still alive, then the many-worlds interpretation is true, because there is only about a one in 1018 chance of surviving in front of the Quantum Suicide machine for a full minute, so the only plausible explanation for your survival is that the MWI is true and you just happen to be the one universe where the atom's 50% chance of decay turned up "no" sixty times in a row."
Super Mario World vs. the Many-Worlds Interpretation of Quantum Physics, Mechanically Separated Meat, 3 Feb 2008
(The Super Mario World video is quite good, as well.)