I usually have a lot of open windows when I'm on Linux. I saw this feature when my classmate showed me his Mac Book running Snow Leopard. Whenever he hover his mouse to the top-right most part of the screen, all of the open applications will show up. And then he can click any window he like to bring it in front. Something like this: http://en.wikipedia.org/wiki/File:Exposeleopardall.png
It's called Expose in Mac OSX. Can I achieve the same effect in Ubuntu? How?
Thanks in advance!