Bonneville has released the full version of CPS for free - it previously cost $150.

CPS is a realtime interactive programming environment for audio, MIDI and other media & I/O. Patches are built by placing objects and making wires between them. Areas of interest are sound design, algorithmic composition, DSP, electronic/computer music and education. CPS can be used in any realtime situation where sound plays a role.

Built-in objects allow you low-level access to audio MIDI and other I/O, and any processing in between. Objects include audio and MIDI (hardware&file) I/O, fourier analyse, filters, noise generators, envelopes, delays, LFOs, effects, and many more objects like tables which you can fill with 'generators' (a feature which derives directly from Csound), several network options, joystick, serialport, video processing units (through Quicktime) for layered playback of video & images, VST hosting of VST plugins/instruments, MP3 decoding, and all MPEG-4 Structured Audio opcodes (which are based on Csound).