One of my favorite albums ever:
Medulla by Bjork
Every piece was constructed and engineered with human vocals, no other instruments.
Incredibly psychedelic and powerful...

I used to dose and have it playing in another room, with a stereo playing something else in the bathroom or something, like Ali Akbar Khan, or Beethoven.
The occasionally synchronizations between the two music sources were hilarious ;]

Just thought I'd share for anyone who's never heard it...Nothing quite like it!