Renoise

From Renoise: Renoise is a sophisticated music sequencer and audio processing application for Windows, Macintosh, and Linux. Renoises rock solid stability makes it ideal as a live jamming tool. You can map almost every part of the interface to a MIDI controller, run your guitar through a Line-In Device and distort it with native effects, or just use it as a drum machine; a sampler on steroids. Renoises open API allows programmers to easily extend Renoise. With a few lines of code you can add the features or tools that you always wanted but never dared to ask for. Renoise is based on mod trackers. Mod trackers are characterized by displaying and editing music in an easily understood grid known as a pattern.