JythonMusic is a software environment for developing interactive musical experiences and systems. It facilitates computer-assisted composition, providing composers and software developers with libraries for music making, image manipulation, graphical user interfaces, and interacting with external devices via MIDI and OSC, among others. This environment is free and open source, intended for musicians and programmers alike, of all levels and backgrounds. Here is a first-year university class using it to create a Laptop Orchestra performance of Terry Riley’s “In C”.