I have this music-centered idea. You know how songs have verses, and choruses, and bridges? In other words, sections? Well in some video games (ex: Ocarina of Time) the soundtrack is composed of multiple section (in OoT's case, 11-12) and they are chosen at random. They all work with one another, and it allows the music to be endless without being completely repetitive.
Let's say the segments are each about 8 seconds of music, and labeled A-J.
First playthrough, it could pan out like this: A B A D F E A G A B
Second time, it could pan out like this: A F A D H G B C E J
And so on.
Then there's another technique, called adaptive music, where there are layers to the track, and depending on a certain variable (ex: threat level) more instruments fade in.
Here's an example I made:
http://www.youtube.com/watch?v=geFpTqvaIJQGames like Mass Effect and Lost Planet use this.
Here's my idea: combine the two. Layered music that's endless, because it's comprised of 10+ segments that are chosen at random. Or NOT so at random? Maybe certain segments will only play based on certain criteria? Like low health lets the more tense segments play, or getting to a certain point in the level allows other segments to play.
Using this kind of technique, you could score an entire level of play, including exploration, minor battles, cutscenes, and a final boss battle ... with ONE "track," a track that adjusts depending on how fast the player moves through the level. A track that reserves segments of music for key moments, and adds layers or intensity when enemies are around (or you're dying).
I would make a demonstration of this myself, in some kind of game format, but ... hell, I don't know how to use any game making software (well).
What do YOU think?