Compiz is a compositing window manager that uses 3D graphics acceleration via OpenGL. It provides various new graphical effects and features on any desktop environment, including Gnome and KDE. (Short version: Wobbly windows and stuff)
Compiz Fusion is the result of a merge between the well-known Beryl composite window manager and Compiz Extras, a community set of improvements to the Compiz composite window manager. Compiz Fusion aims to provide an easy and fun-to-use windowed environment, allowing use of the graphics hardware to
... [More] render each individual window and the entire screen, to provide some impressive effects, speed and usefulness. [Less]
Cairo Composite Manager is a versatile and extensible composite manager which use cairo for rendering. Rendering can be done in 2D or 3D, using Xrender and Glitz backends. Plugins can be used to add some cool effects to your desktop.