QuartzCube is a configurable, wide-angle, rotating video cube.
The easy-to-use interface allows you to immediately apply different videos or still images to the faces of the cube. You can also alter the tension of the roll axis to adjust the rotation of the video cube. But watch out, it is highly addictive. A lava lamp for the modern day.
QuartzCube is totally free and runs on Mac OS X 10.4 and 10.5.
Most video formats are supported, including QuickTime, MPEG4, AVI and many others, and all the popular image formats. QuartzCube allows you to save your cube configurations and reload them.