Here is an interesting musical setup that only requires fingertips and a stylus to play: the Korg DS-10 cart in one Nintendo DS, Electroplankton in another, Bloom on an iPhone, Mokugyo on an iPod Touch, and a Kaossilator on the side.
I can think of several 20th-century experimental composers whose heads would asplode if they could get their hands on this rig.
Over Christmas I upgraded to an iPhone and I’ve already downloaded a bunch of music-making apps for it. Bloom–which was cocreated by Brian Eno–is an interesting, intuitive, and completely mellow way to create ambient music, and working it doesn’t require any facility with an actual instrument. I’m also enjoying RJDJ, which uses everything from the iPhone’s mike to its accelerometer to record and manipulate sound. The Ministry of Sound-branded iDrum isn’t as kooky or experimental or user-friendly as the others, but if you’re interested in sequencing beats and synth parts while you’re on the bus it works pretty well. After watching this video I downloaded Mokugyo, a simple virtual instrument consisting of a metal bowl and a wooden gong that you can touch to “strike”; it doesn’t really do anything else, unless you count “With Cat” mode, where every time you touch the screen the background switches to one of a small number of cat pictures, which is a feature more apps need.
For more on new musical interfaces you can check out my Sharp Darts on the topic.