I think for many people their first introduction to experimental music is soundtracks. Whether you have realized it or not you probably have heard it in some of your favorite TV shows or films.
One of the early pioneers of experimental music is Daphne Oram.
In listening to her music, I realized I had created some pieces that were similar in sound to hers.
I don't know if I actually heard her works before, but she did work with the BBC Radiophonic Workshop and her sounds were used in Doctor No, Goldfinger, and a number of other films, so it's possible.
I also learned she used a similar technique for some of her music creation. She was the creator of Oramics, which involved drawing shapes on film that was then translated into sound by a machine.
Some of the music I create uses software to translate images into sound, so it's a very similar process. I can choose how slowly the software "reads" the image as a score, the note range for the sounds, what sounds are used, how the colors in the image are interpreted, etc.
For a good read, check out the Wikipedia article for more details.