I fall asleep to YouTube -- not watching, I just put on a boring documentary with a monotone narrator, just loud enough that I can hear the voice. I don't even really discern the words. And it distracts my brain from whatever else I'd be thinking about and I fall asleep more easily. Not sure why this is, I guess it's like having someone read a bedtime story to a kid.
I have a premium account so there are no ads.