Once I was in a motel room where it was possible to see the TV from the back. My husband was watching some rather quiet show (I think "Junkyard Wars," which has no explosions or gunfire). Nonetheless, around the silhouette of the TV I could see many, many flashes of brilliant light, like little lightening bolts.
When you watch TV (or movie, or computer) that light impinges on your retina and wakes you up.
Me, when I really can't sleep, (PG Woodehouse having failed) I get up and play mountain dulcimer for a while. ============== Thanks for the warning about Lunesta.