Moving Rocks
Stumbled upon a Wiki site that I thought was extremely interesting.
Did you know that there’s a record of stones that move by themselves? Called the "sailing stones", "sliding rocks", or "moving rocks", these can be found in Racetrack Playa in Death Valley, California. Nobody knows why these move: the rocks are too heavy to be moved by wind. Other factors are also not considered, since if water or anything else moved them, the tracks of the rocks would’ve been disturbed. They also couldn’t have been moved by humans, because the footprints would’ve appeared on the ground pretty easily (the soil/sand is such that anything that happens on the surface level would leave marks on it).
You can read more about it here.
So is that why the place is called Racetrack Playa? Because the rocks race each other?

August 24th, 2009 at 8:19 am
Think I have a theory. Maybe at night, the little Racetrack Faeries Elephants come and push the stones along, just to confuse us! Or, possibly, the rocks are really transformers in disguise, waiting for their decepticon leader to call them from the stars… hmmm, it’s got me thinking!
August 24th, 2009 at 1:03 pm
There’s an underground headquarters somewhere in that area. Those lines are probably tracks made by special vehicles then they went underground into their base or the rocks and lines were placed intentionally to divert the enemy’s attention from the true location of the secret base.