Speaking of "ur-tunes" (as lamarca said), Arthur C. Clarke -- in his collection of humorous science fiction short stories, Tales from the White Hart -- has one story (can't remember the title, sorry) in which the narrator describes a sound engineer who invents a machine to find the perfect jingle. You know the way a song will get stuck in your head and go round and round for weeks?

The inventor analyzes lots of popular jingles and tunes and has a machine try different combinations and permutations of their common elements.

The machine finally hits the right combination. The inventor manages to set the machine to repeat the tune, and listens to it enough times that it sets itself into his head SO thoroughly that he can no longer pay attention to ANYTHING but the tune in his head. Not even shock treatment will bring him out of it. *G*

Funny book! (all y'all music-type people will also like the first story in the collection: "The Silencer", which is available on-line at this site. Enjoy!)

BB,
NightWing