Cool idea- Music on Demand.
1. Contained original or otherwise-legal music in it.
2. Wanted players to be able select songs and play them whenever they wanted to, as opposed to whenever the game designer said that they should hear the music.
Here is how to do it. It's really super-simple:
1. Make a Class 1 weapon. Give it a Lifetime of 0.000001 or whatever. Really short. Don't have it do damage, have a Flash, or anything. Give it a null FX entry, so you won't see anything.
2. Play the song as the weapon's firing sound.
3. Make the refire_rate as long as the song (down to the nearest 10th of a second- round upwards).
Aaaaand... there you go. Clone the "weapon", and add new Sound entries for each song. Encode each song with the mp3 Frauenhofer codec, and then have a Base somewhere sell these "weapons". Players can either have the song start the second they start firing, or disable the "gun" and play the song manually.
If you make use of my XML Toolkit mod (which drops all guns to level 2, among other things) you could go a bit further with this concept, and go into Shiparch (and any added ships) and get rid of every Gun mount for Class 4-10. Then make every ship have, say... 5 Class 3 hardpoints, buried in the center of the CMP. These "gun" hardpoints would then become a player's "cd-deck". Players could then carry around 5 songs, and they wouldn't interfere with weapons