There's this dry lake bed in Death Valley called Racetrack Playa. No, not Racetrack, playa, "Racetrack Playa".Racetrack Playa is an almost perfectly flat dry lake bed nestled between the Cottonwood Mountains to the east and the Last Chance Range to the west. During periods of heavy rain, water washes down from nearby mountain slopes onto the playa, forming a shallow, short-lived lake.
So what? Well, erratic rocks slide and drift along it's surface, leaving odd tracks. Best explanation is that the high winds in the valley conspire with a specific amount of wetness in the mud to send these rocks gliding along the surface, much like curling.
Either that or it's magic.

This map is a GPS vector analysis of the rock's motion, as done by Paula Messina, she happens to have the best site I've seen about the phenomenon, It's here.