We had been advised to arrive at the Marfa viewing center before sunset in order to get our bearings, and to spot the radar tower to the southwest and the highway beyond to Presidio. As it got dark people around us started claiming to see the lights, but my wife and I were certain these early lights were from the cars and tower, but we did not dissuade their enthusiasm.
As the sunset was deep red in the west, and for the next hour +/-, with the sky very dark to the south and southeast, we started to see a few white lights on the horizon. 1-2 or 3 at a time, with some moving down in a zig-zag method, then others would move left and then right. Some of the white lights would turn pink-red and then back to white. Some of the white lights turned brilliant white and then disappeared. By 10:30, the activity had slowed considerably that we all soon afterward left. (plus we wanted to check in on the UT football game!). It crossed our minds when viewing that maybe someone was out there on the hills playing games with us, but of course, this has been going on for a century or more, so I guess we actually experienced them. One draw back was the head lights coming from Marfa to Alpine. Being a Saturday night, I think there were more cars, and thus more light than may be expected other times and it was a bit distracting.