DelVJ is a gpl'd software for realtime 3d composition and algorithmic video remixing that uses gtk, python, glade, php and puredata.
Tries to use best from opengl and software video remixing worlds to achive highest perfomance and visual impact. Through gtk, osc and web interfaces it tries to make everything really easy for the user.
Also tries to leverage different protocols as OSC, midi, video libraries like pdp, pidip, 3d libraries like cal3d (for animated 3d characters), gltt or ftgl for 3d texts.
Delvj also just started to package some free media, but this is only starting, also lots of videos by many collectives are being recovered for the community (keep watching :)).
It can be controlled through OSC, and has web and gtk interfaces.
Also comes in english, spanish and catalan, soon to come more languages.
For Pixel fests of many kinds