Why not take the idea of generative sound literally?
John Conway certainly set the standard during the early 1970s for taking the programming-as-organism metaphor at its word with his Rules of Life. That was his game-like system in which small cellular automaton expand into a pulsing pixelfield of what resemble living, if not breathing, digital beings, especially as they get more and more complex.
Conway's mix of visual play and algorithmic ingenuity informs Seaquence.org, which may just be the coolest non-iOS interactive audio-game (or sound toy) to appear in 2010.
Seaquence is a browser-based sequencer that looks like a petri dish. Or, the more you play with it, a petri dish that acts like a sequencer. You develop your own set of paramecium-ish creatures, each of which acts like a so-called "step sequencer." That means that it plays a sequence of notes that are notated in a grid-like pattern. Make one creature, toy with its musical DNA (affecting "waveform, octave, scale, melody, envelope, and volume," as the instruction explain), and then add others to see how they interact.
Seaquence is an original project from Gray Area Labs, created by the artist-developers Gabriel Dunne, Daniel Massey, and Ryan Alexander, with support from Gray Area Foundation for the Arts, an arts organization based in San Francisco's Tenderloin District. There's going to be a special GAFFTA event on New Year's Eve in San Francisco that will provide new members of the organization access to a special gaffta.org edition of Seaquence, as a kind of financial support mechanism for digital artists.
Seaquence will, however, its developers assured me, always be free. I've been interviewing one of the Seaquence developers for a series of articles about interactive sound apps. Asked about upcoming Seaquence improvements, Dunne provided a glimpse of what's next: "Some of the more obvious additions will be the ability to control the tempo and effects. We also plan to introduce user accounts with the ability to save your work under your name and favorite seaquences you like. We're building up to a larger concept of an explorable ecosystem, and consider the project perpetually in progress."