It's one of the best ways to settle a dispute, requires no tools or additional game pieces, is easy to learn and impossible to master. It's rock, paper, scissors, or roshambo. For the truly nerdy among us though, things can be taken to the next level by adding Spock and lizard. And even more nerd cred goes to Takamichi Irie, for building it in LEGO (with the new half round tile even, spiffy).
UPDATE: Things got very nerdy, well played sir, well played.