From this article.
For the record, I always had a great deal of trouble sleeping. I went through most of my school days exhausted from insomnia the night before. I just could never get to sleep, starting from the onset of puberty. In my senior year of High School, I saw at the local Caldor (anyone remember those?) a subliminal tape offering to cure insomnia. Side one was a man talking you through relaxation techniques: basically low-powered meditation. Once in a relaxed state, he reminded you how good it felt to sleep, and how easy it was to get to sleep. Side two of the cassette was pretty tinkly music over the sound of surf, while the man’s voice could occasionaly be heard muttering in the background.
Long story short, I tried it, it worked, and in the space of six months, I was falling asleep within 5 minutes of my head hitting the pillow. I still can.
Now: I don’t know how truly effective the subliminal side of the tape was. I would always start to feel drowsy after listening to it for a while, but I have a feeling that was a pavlovian response of sorts; the same surf noises were used in the background for the controlled relaxation session on side one. Wish I still had the tape, btw. The music was vaguely remeniscent of Eno’s Music for Airports, IIRC.
Anyone have luck with these things?