I discovered this through Ain't It Cool and their horror countdown. This is actually a documentary on Netflix.
The Nightmare is all about night terrors. This doc includes interviews with several people who suffer from night terrors and they talk about the evolution of their illness. As someone who used to have these himself, I found this very fascinating. There are commonalities between the waking dreams people have and, oddly, a huge overlap with alien abduction lore. The stories are fascinating as are the times when a seeming religious intervention stopped the terrors.
The main selling point on this documentary is how scary the reenactments are. Filmed exactly as the people on in the doc describe them, the reality of seeing some of these nightmares come to life can be unsettling at best. There is also a brief discussion of how the Insidious movies have done a decent job of capturing the feeling of night terrors on film.
Your mileage may vary if you have never had the misfortune of having a night terror yourself. I found the doc very fascinating and worth the watch.