  The locker puzzle is a game played by multiple players against a referee. It
has been previously shown that the best strategy that exists cannot succeed
with probability greater than 1-ln2 \approx 0.31, no matter how many players
are involved. Our contribution is to show that quantum players can do much
better--they can succeed with probability 1. By making the rules of the game
significantly stricter, we show a scenario where the quantum players still
succeed perfectly, while the classical players win with vanishing probability.
Other variants of the locker puzzle are considered, as well as a cheating
referee.
