Ubuntu 9.04 comes with a set of Visual Effects excluding 3D Desktop Cube. Thanks to one of my friends I was able to find some information on how to enable it using Compiz Config Settings Manager.
This is how to do it; First install Compiz Config Settings Manager by typing the below command in a terminal window.
>sudo aptitude install compizconfig-settings-manager
Then open the CompizConfig Setting Manager using System -> Preferences -> CompizConfig Settings Manager.
That’s all :-) Everything you needed to configure visual effects can be found in this window. Moreover it provides information on short-cut keys to trigger different effects. You may find a key called “Super” in that content, it refers to the Windows Key in your keyboard. Try