Collapsable windows for website?

I am looking for at least an example of a slow moving expanding section, or pane, for a website i'm working on. As in there is a body to a website and a head, at some point someone clicks on an icon that makes the body the entire screen, but when they click in X or an arrow pointing down, it glides the head back into the screen and now there is a head and a body again.

Thanks!