When hanging a horseshoe some people believe that the ends should point up, and some believe that they should point down.
For those that follow the up pointing tradition the belief is that if the direction were reversed all the luck would fall out and drain away.
For those that believe in the down pointing tradition the belief is that all the good luck will continually rain down on those that pass beneath it, and fill the home with good luck.
Many simply enjoy the added charm of hanging a horseshoe over a door regardless of its orientation.
If you'd like some solid tips for improving your luck, check out Tips for Welcoming More Good Luck Into Your Life.
In other superstition news, one of the more... ripe ...superstitions making the news is that UFC fighter Bobby Green doesn't shower in the days before a fight; he's been doing this since a 2004 win over Hermes Franca at UFC 46.