It's Beethoven's Ninth, slowed down by a factor of about 25. That is one second of the original takes about 25 in this version, called 9 Beet Stretch.

It's very listenable ambient music, with some surprising movement. Some of the passing chords can be very dark, and stretched tympani could be the very soundtrack of Doom, but after a while it all returns to the dominant or subdominant.

What's especially cool is you can listen to it streaming 24/7. Perfect for hacking sessions.