Have you ever seen the Marfa Mystery Lights in Marfa. Texas? What do you think they are?

Answer 1

Yes I have. Despite the misinformation posted earlier there is a clear dividing line between car lights that are seen and the mystery lights (as anyone that has actually been to the location is well aware). Of course the car lights fail to explain the reports before automobiles (or the behavior of the lights) but then I guess stage coach lights and campfires could be used as typical debunker (read bad) science.
Most people that have actually investigated this phenomena have suggested that it is a natural phenomena and probably reflections from as far away as Mexico (via some unusual weather effects). The unusual weather conditions would explain why they do not show up on a frequent or regular basis. Reflections would explain the difficulty in locating the source of the lights.
I know they are not car lights and they are not direct reflections (like the Brown Mountains) beyond that it is open for testing and experiments.

Answer 2

This has been definitively shown to be headlights. The phenomenon has been reproduced. I know the local Marfa tourism bureau may do all they can to keep the controversy alive, but the case has been closed.

Answer 3

while I have not personally seen these lights, I have seen many shows where these lights were discussed. at this point, the best answer has been ball lightning. Thats not to say thats what they are, just thats the best answer they have come up with.

Answer 4

Probably just car headlights + wishful thinking.

http://skepdic.com/marfa.html