Are you having trouble sleeping lately?
Have you tried reading before bed?
What’s that? You’re reading an e-book?
Research is starting to converge on a pretty clear picture of how the brain knows to go to sleep, and the lack of light is a huge player. That means that reading on a backlit electronic display prevents you from going to sleep. It has to do with melatonin. Here’s an article summarizing the whole story, but if you’re thinking you want to be unconscious in the next hour, turn off your computer/tablet/phone/whatever and pick up a book. You can read about sleep when you wake up.