Electroplankton is an interactive music video game developed by the Japanese interactive media artist Toshio Iwai and published by Nintendo for the Nintendo DS portable gaming system. This unique software allows one to interact with animated "plankton" and create music through one of ten different "plankton themed" interfaces. This title is commonly not regarded as a video game in the fullest sense, but rather a "toy" because there is no objective, timer, or top score. Everything that the game has to offer is available from the beginning. The first-run edition of Electroplankton in Japan came bundled with a set of blue colored ear bud headphones.
(Source: http://en.wikipedia.org/wiki/Electroplankton)
Ten different digital types of plankton allow players to explore different play and influence options. Sound and graphics can be changed by tapping the touch screen on the Nintendo games console with a pen, leading to fascinating new sound and image compositions thanks to the resulting interactions.
http://electroplankton.com
(Source: http://www.aec.at/en/index.asp)