Songs to Test By

Fresh from the Aperture Science Psychoacoustics Laboratory is the aural stimulus package Songs to Test By (also known as the Portal 2 soundtrack volume 1). It's freely available for download by anyone, you can get your copy here http://www.thinkwithportals.com/music.php. I'm listening to it as I write this. If you're a fan of the game or interested in electronic music at all then I would highly recommend it. It's great to hear it clean without being distracted by GlaDOS and Wheatley while you're busy trying to solve puzzles. I've not heard it all yet but my favorite so far is The Friendly Faith Plate.