The Beat Jigsaw

The beat jigsaw seems to be a good interactive artifact:

The Beat Jigsaw is a jigsaw puzzle which the user can play with to create music and vj style graphics. The interface is a number of wooden blocks which can be slid around a table top. The arrangement of each piece in a certain position triggers a specific sound and corresponding video loop via a projector. By utilizing more and more pieces the user can build layers of samples and create his/her own music. The Beat Jigsaw is an Interactive Multimedia Installation which invites audience participation. It is a musical instrument, an immersive experience and most importantly, a lot of fun to play with!

As the designers says, it's "simple accessible djing for everyone" :)