Melissa Dahl for Science of Us on a study on how to fall asleep when you can't, something I struggle with frequently: 

Late at night, when you've been trying and failing for hours to fall asleep, perhaps the thing to do is to try not trying. According to a 2003  study recently  highlighted by University of Hertfortshire psychologist Richard Wiseman in his "59 Seconds" video series, when insomniacs tried to force themselves to stay awake, they were able to fall asleep.