Most computational systems take for granted the servitude of computers, hoping to make them invisible entities that intuit our needs, and seamlessly respond to them. Linked with this idea is the one that we can formally analyze any situation, and program an overarching structure for the computer�s task. Much of this assumption stems from the military origins of computers, and the perceived need for total control; the experiences we have with computers reinforces this paradigm of direct manipulation. Most human activity, however, does not follow such formal structures. Our computer monitors routinely sport half a dozen post-it notes, evidence of the weakness of completely formal systems. Humans routinely improvise their activities, from casual social encounters to their first experience with a machine. For Improvitronic Islands, a small group at the Media Lab worked with two masters of Jazz improvisation, George Lewis and Toshinori Kondo, to develop computer music systems that help children learn principles of improvisation. The system enabled children to quickly use two of their most basic faculties for music making�body rhythm and voice�and to use them in collaborative, improvisational performances.