WebPlayer lets you listen to what a URL sounds like so you can groove along while surfing your favorite sites (Shockwave player required). The creator says:
"Fortunately, I stumbled upon the serialist composers and their work - people who used strict mathematical formulas to structure their music composition, effectively generating music out of numbers. By implementing a similar process to the likes of Schoenburg, Messian et al, the output became structured, rhythmic and more musical in nature. The formulae that the webPlayer utilises are quite complex in nature, but fundamental to the process of its musical generation, so I have included a complete breakdown of them here."
A more complete description of the process is available. It would be nice to see an updated version of WebPlayer that introduces a bit more variation into the music...most of the sites I tried sound about the same.