Some (but not all) humans experience the autonomic sensory meridian response, a sort of tingling sensation caused by various visual and auditory stimuli. I think it's partly an adaptation to encourage humans to bond through social grooming (removing fleas from hair, etc.). It often causes sleepiness.
So: one thing I've been trying is to use ASMR to make myself go to sleep faster and sleep better, by playing ASMR-inducing sounds through sleep-suitable headphones. I don't know whether this works (planning to measure it sometime) but it definitely feels nice.
To test whether ASMR works on you, and to get ASMR stimuli, go to http://www.reddit.com/r/asmr/top/?sort=top&t=all .
I'm planning to try combining this with periodic audio of someone saying "you are dreaming", as a way of inducing lucid dreams.
This has a name and a WIkipedia article and a subreddit? Couldn't be carvier at the joints of reality if it tried. Thank you! (Not sarcastic; I've been idly wondering about this for about four years.)
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.