Menu action to enlarge on mouse over

Hi,

I´m trying to make a menu like this:
A bar with several blocks beeing the buttons. Each button with the same size.
When the mouse is over one of them, it´s size get´s bigger, let´s say 3 times it´s original size, and the other buttons get smaller, to make space fot the morphing one.
I´ve attached an image explaining what I´m looking for.

I know I´ve seen this kind of menu somewhere, but don´t know what is called to search for it.

Does anyone know a link, fla or could point some directions on how to implement this menu?