The "Mist Bench" from designer Gwenael Nicolas utilizes coarse knits of optical fibre that respond to human movement. As you get closer, the bench glows brighter.
The Mist Bench is described as a "light sculpture," and it set to make it's debut at the '09 Senseware exhibition' at Milan design week. So, I wouldn't expect to pick one of these up at your local furniture store anytime soon. [Tokyo Fiber via Designboom]