Hello! Thought I'd share this, though most people probably have some sort of idea of this already.
I read an article recently by some sleep researcher or other about the light emitted from computer monitors, TVs, and cell phones. The short-length light waves from these things will greatly disrupt the production of melatonin. The researcher suggests not using them for an hour or more before bed time to get the easiest sleep.
Just crossed my mind and thought it might be useful for some people to know. Have a nice day :)