I was doing some digging today, looking in the Compiz settings to see if there was something similar to Expose, from the Apple OS – and of course, there was. If you open the Settings pane under System>Preferences>Advanced Desktop Effects Settings, you will be able to scroll down to a heading titled “Window Management”. In here there is an option called “Scale” – enable that by clicking the checkbox to the left of the icon. By default, the trigger is Shift+Alt+Up, but if you click on it, go to Bindings and find where it says “Initiate Window Picker”, you are able to change it to your preference. The first option titled that is for choosing a “hot corner” to trigger the program, while the second is for using a keystroke.
Note: You must install Compiz Fusion in order to get this effect to work. To do so, read the post on installing common programs in Ubuntu.