GULCII (graphical untyped lambda calculus interpreter) is an experimental live-coding environment using a minimal abstract language from the foundations of computer science. The internal state of the virtual machine is presented, showing the process of computation.
GNU/Linux (Ubuntu Lucid) can probably use free drivers, but untested (so far)
Repository: https://gitorious.org/maximus/gulcii (branch 'master')
Software: mostly self-written Haskell code (GPL), using GTK + Cairo sonfication with self-written Pure-data patches ghc, xorg, xfce4, devilspie, gtk, cairo, gtk2hs, puredata, jackd, qjackctl, meterbridge, ecasound