Luz open-source live motion-graphics editor

Found this doing a search for linux Motion Graphics Software.

Luz is an open-source live motion-graphics editor and performer.
Luz offers polygonal shapes, images, animated gifs, typography, paint canvases, and 140+ effects to use on them.
All effects can dance to the beat, react to audio, or be controlled live from:
Gamepads, Joysticks, MIDI knobs & sliders, MIDI Pianos & Drums, WiiMotes, Wacom Tablets, Kinects, and
any app that can send OpenSoundControl.

Luz has many experimental features, such as 2D Physics support using Chipmunk

Luz is developed by LightTroupe, a collective of artists who uses Luz to create audience-interactive visuals.
Luz is written in a beautiful and accessible programming language, Ruby.
Luz Actors and Effects are supplied by plugins that are also written in Ruby.
Luz is free and open-source software, available for you to study, play with, and change.
Luz runs happily on the free and open-source Ubuntu operating system.
Luz uses OpenGL to unlock the amazing possibilities of your modern video card (NVidia, ATI, Intel X3100 or better).
Luz speaks OpenSoundControl natively. Luz Spectrum Analyzer and Luz Input Manager send OSC to Luz.
Luz Studio’s interface is built with Ruby, Gtk, and Cairo for icon and beat monitor rendering.
Luz Input Manager is written in C++, Gtk, and uses SDL, libwiimote, XInput, and PortMIDI for input device support.
Luz Spectrum Analyzer is written in C++, Gtk, uses the FFTW library for audio analysis, and OpenGL for rendering.