Mike Lischke's <a href="http://www.lischke-online.de">Soft Gems</a> site is a good example of this cool control in use. It uses accelerating/decelerating animation and opacity progression to show/hide menus. Very slick ... and it's cross-browser. (<a href="http://www.dynarch.com/products/navbar/">Dynarch Navbar Home Page</a>)