The site is a script library. Built on javascript effects and such. To use them you would download their package and extract all of the .js files into some directory on your webserver. Then you use a <script src=""> type tag to import them onto the pages you want. Different files also have different effects. If you look on the demos page it will show you what some of them can do. An example of how to make something fade out when you click on it would be like this:
Code:
<div id="blah" onclick="Effects.Fade('blah');">stuff Here</div>
If you look through some of the stuff on the documentation they have some better examples of how to use it. Such as using the draggable effect, which is one of my favorites.