The official viewing area for the Marfa Lights is about nine miles east of town on U.S. 90 toward Alpine. The lights are famous, disputed, and unreliable, which is part of their charm. Some visitors see strange points moving over the desert; others see headlights, stars, and a very dark horizon.
Go after sunset with modest expectations. The viewing area is free, easy to find, and still worthwhile on a clear night because the desert sky does not need the mystery to do its job.