Sonic Pi - Sonic Pi is a new kind of instrument for a new generation of musicians. It is simple to learn, powerful enough for live performances and free to download.
Wob FX 2 - "Looking for wobble? Look no further.
SuperCollider - A real time audio synthesis engine, and an object-oriented programming language specialised for...
Klangmeister - Klangmeister is an open-source, live coding environment for composing music in your browser.
ChucK - A strongly-timed music programming language
Nyquist - Sound synthesis and composition language with integrated IDE