This is the coolest fucking thing I have EVER seen!
Go play. Now.
For the lazy, it's perhaps the largest musical instrument in the world. It's a 200 meter long, 45 meter high empty silo (built by le courbousier I believe) in Montreal, which has a large set of speakers installed in it as well as a microphone. You can make the speakers play any sound you want and hear it live (well, 30 second delay) via realaudio.
Holy Fing shit.
Somone's making it play some elvis song right now.
The accoustics in that place must be nuts.
(I know, I'm supposed to be working, but I took 10 minutes to follow a random link and WHEEEEEE!)