Tidal is a language embedded in Haskell, for the live coding of pattern.
Subscribe to the tidal mailing list if you want to chat, ask questions or contribute:
You can find some documentation for how to install and run Tidal here.
For some videos demonstrating some aspects of Tidal, have a look at this blog post first.
The sourcecode is available under the GNU Public License version 3 (or later) on github.