Bjork is using both a Reactable and a Lemur on her new tour, have a look above for a video of her on Jools Holland. The Reactable is a tangible user interface that allows multiple users to interact with a synth/sampler using small perspex blocks, and get visual feedback directly from a projection through the table. The lemur is also a multi-touch interface, although it is a lot more compact and you use your fingers to interact with it.