Sliding effect features on mootools

Hey Im trying to code a similar effect to what is on the mootools front page with the sliding effect. A demo is found in there demo section:

http://demos.mootools.net/Fx.Elements

Just wondering how do I get it to work? I code XHTML/CSS but not javascript.

I will be using the effect on the section with "templates, tutorials, navigations, forums" on this template.

Edit: think ive worked it out apart from one thing. How can I get the far right item "forum" in my design to expand to the right with the rounded edges to the right? Can think of a way to do that apart from having the rounded edge a background image on the container on the far right. Only thing I would then need to work out is to make the forum expand to the left instead of both ways.