Reactable: A multi-user electro-acoustic music instrument

Though it looks like more of a computer interface rather than an instrument, the Reactable that has been developed in Spain is a multi-user electro-acoustic music instrument that features a tabletop tangible user interface. Many users can concurrently have total control over the instrument by stirring physical artefacts on the table surface and making dissimilar audio topologies in a kind of tangible modular synthesizer. Via: Dvorak