The files are mp3 sitting around in a folder, so it isn't even hard to do.

I mix them with the better tracks from Total Annihilation. They go together very well.
(I'm not where I can verify where I add the soundtrack from the Wheel of Time game into the mix, though -- is it there, or with my combination of Age of Wonders 2 and Outland...?)
Honestly, at least half my music is game scores.
Edited to add: it occurs to me we ought to have a thread in the Music/TV/Film subcategory dedicated to game scores...