SuperCollider - A real time audio synthesis engine, and an object-oriented programming language specialised for...
Vvvv - vvvv is a graphical programming environment for easy prototyping and development.
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.
Processing - C++ and Java programming at the speed of thought.
ChucK - A strongly-timed music programming language
Vuo - Design and build live interactive media.