The world's quietest room will drive you crazy in 30 minutes, apparently.
http://news.discovery.com/human/life/worlds-quietest-room-will-drive-you-crazy-in-30-minutes.htm"The key to the level of silence is the fact that the walls, floor and ceiling absorb all sound, rather than reflecting it, as most surfaces do. Thus the term anechoic: no echo. It’s so quiet, you can hear your own organs: your heart, stomach, even your ears, which make a tiny amount of noise. It turns out that it’s not an especially pleasant experience, especially in the dark. The longest anyone has ever spent alone in the chamber? Forty-five minutes."
