This is a very cool program that is useful for stressing video processors. It's a "real-time dynamic range image based lighting demo". Called Rthdribl, it's free to download at this link:
http://www.daionet.gr.jp/~masa/rthdribl/
Running this while running GPU-Z is excellent for testing new cooling solutions, as well as performance on video equipment. With these two together you can see FPS during any number of different lighting and shading scenarios, while also watching GPU load and temperatures.
Plus, it's just downright mesmerizing to watch.