From Imagine Technologies:
DreamRender replaces your desktop wallpaper and icons with stunning animations. You can choose from 1000's of different effects ranging from slow and peaceful through to manic, most effects can also react to your currently playing music. If you think some effects are missing then easily make up new ones using your own images, videos, and icons. For complete customisation of your system DreamRender can apply textures and colors to your windows, make them transparent, and produce amazing effects every time you move your mouse.