Intro to Genetic Algorithms, Music
If it'll help wrap your mind around it, this method could be applied to music. Come up with a lot of tunes which are random notes. Some may sound better than others. Then make a new set of tunes by taking the best tunes and exchanging and mutating some of their notes (which is their genetic code). The next generation will have some of the properties of the good songs from the previous generation and maybe even be better. Repeat until you've got a hit.