This would be super addicting..someone needs to make an online version of this!!
From the Reactablesite:
We created Reactable Systems with the vision to redefine the way we interact with computers. Using the knowledge we gained through the Reactable musical instrument we are developing intuitive products focused on the promotion of creativity and the mediation of culture. In order to achieve this we are applying the latest technologies in human computer interaction, music technology, graphics and computer vision.
Our first product is the Reactable, a novel musical instrument that has gained international reputation and received several worldwide awards. Based on the successful concept of the Reactable we are working on new applications enhancing the technology and expanding its applications.