[Update: As of now it seems as though the soundtrack has been removed. You can still buy it however from most online retailers.]
Back in 2004, engineer-turned-film-maker Shane Carruth unleashed unto the world Primer, a low budget sci-fi time travel movie that to this day still astounds viewers with it's complex narrative.
Upstream Color, his follow-up film, proved to be more mind boggling than Primer and managed to amaze audiences as well as infuriate them. Apparently a big piece of the appeal was the music, also composed by Carruth, and it is now available to listen to online via his SoundCloud page.