I saw my first show of TBA yesterday: A strange, intimate little piece called The Quiet Volume, which is set in the Central Library and designed for two people at a time. You grab an iPod, sit down next to a stranger, and are guided by narration and text on a tour through the stack of books in front of you.
It was really good! And it made me feel like I was going crazy. I've got a full review over on our TBA blog.