Copyright Music Hack
Given that there are a limited number of musical tones, it seems to me there's a limited number of songs that could be written. Could you autogenerate songs and then demand licenses for every new ditty that came out? How about if you simpify the idea to reduce the number of combinations? Just go for a accomplishing a "similar sounding hook", which might be enough to cause trouble.

4 bars of 4/4

eighthnote of precision

so that's 32 notes to generate (to be really crude, we won't even generate tones of differing length  a quarternote occurs when 2 consecutive eighthnotes have the same value)

2 octaves of tones (assume no accidentals, which cuts the number of matches, but it would be interesting to know how much), so with silence being an option you get 16 possible values (hey a hex character).

so the number of possible hooks is 16^32, which is 2^128. (Note that each tune could be expressed by a "word" of 32 hexchars.)
Generating every icon takes 2^(32x32) = 2^1024, which is lots longer. (at 100 icons per second it takes 10 years).
An interesting idea would be to reverseengineer a few alreadypublished songs.

take the main "hook", max of 4 bars (or 32 beats of the tiniest precision)

can you play (approximately) that hook with just 2 octaves of white keys on a keyboard (with transposing being OK)? Then you've got a match.
I wish I had a keyboard handy to noodle on...
is this a weird variant of Generative Music?
Looks like Mathematica would be a good tool for this!
Aug'2007: just discovered Quinn Norton's idea called the Symphonic Conundrum.
Edited:  Tweet this!