Sonic Pi
Sonic Pi is your free code-based music creation and performance tool
Sonic Pi is a new kind of musical instrument. Instead of strumming strings or whacking things with sticks - you write code, live. Sonic Pi is a complete open source programming environment originally designed to explore and teach programming concepts within schools through the process of creating new sounds. In addition to being an engaging education resource it has evolved into an extremely powerful and performance-ready live coding instrument suitable for professional artists and DJs. Sonic Pi is a live-coding music synthesis tool used to create and perform music interactively through code.