Various techniques and processes involving manipulating raw data (
images, text files, binaries, etc) which then gets played back as
sound files or maybe - if you're lucky -
music.
See the data benders group or one of many related application including (but not limited to) Coagula.
http://groups.yahoo.com/group/databenders
http://hem.passagen.se/rasmuse/Coagula.htm