In my friend Peter Woit's blog I read an interesting account of an interview to Greene and Kachru, two leading string theorists. Here is an excerpt, which Peter got from the World's Science Festival:
John Hockenberry, the panel’s moderator, asked Greene if he thought experimental evidence would come during his lifetime.
“I’d be surprised,” said Greene.
“And in your lifetime?” Hockenberry asked Kachru.