OLEDs are a 'cold' flat light source - they emit no heat - and thus are safe to touch. This means that it's possible to use them as a touch-light-controller. The Fraunhofer IPMS institute showed (at the Plastic electronics 2008 conference) the world's such device

“The touch function generate a completely new feeling of light. It´s like magic: turn on the light simply by a hand movement,” noted Jörg Amelung, head of business unit of organic materials and systems at the Fraunhofer IPMS.

Read more here (Science daily)