This article is from the Puzzles FAQ, by Chris Cole firstname.lastname@example.org and Matthew Daly email@example.com with numerous contributions by others.
You are in a game of Russian roulette, but this time the gun (a 6
shooter revolver) has three bullets _in_a_row_ in three of the
chambers. The barrel is spun only once. Each player then points the
gun at his (her) head and pulls the trigger. If he (she) is still
alive, the gun is passed to the other player who then points it at his
(her) own head and pulls the trigger. The game stops when one player
Now to the point: would you rather be first or second to shoot?
All you need to consider are the six possible bullet configurations
B B B E E E -> player 1 dies E B B B E E -> player 2 dies E E B B B E -> player 1 dies E E E B B B -> player 2 dies B E E E B B -> player 1 dies B B E E E B -> player 1 dies