I just got this galvanic skin response biofeedback device in the mail a few days ago. Rest your fingers on it and there's a tone goes up as you get more stressed out and down as you get more relaxed. I haven't been experimenting with it very long, but using the device and trying to make the tone go down does seem to be quite an effective way to relax. Housemates have found the tone annoying, but wearing ear-encompassing headphones on top of the supplied earbuds seems to deal with that.
How long do you think it will take for you to know whether it's effective long term? Could you post an update then?
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.