I've been out there. Other viewers nearby saw something. One group of middle aged women with several bottles of wine said they saw the lights. Some guy who pulled up in a Miata with CA plates, the top down, and a cello in the passenger seat wandered off into the desert with the cello and started playing. He came back and said the lights split up, played leapfrog, and changed color. Apparently they danced to his music, and flew around him.
All I saw were the headlights from cars going down a mountain. They all fillowed the same path, came on and went off at the same points, never passed eachother, etc. Also, I can read a map and compass, and verified the next day visually and on paper that those lights were in the exact direction of the road down the mountain.
I'm not saying there are never unexplainable lights there, but all the lights I saw were headlights.
Makes for a pleasant evening in the desert, if you don't mind the crazy people.
Want to see something cool? Look up the Marfa Lights Viewing Center on Google Earth. See those lines just south of it? That's an old air base. Only foundations and roads remain. Interesting history to it.