If you are running Firefox (no idea what other browsers this works with) take a moment to play around with photos.svg. This is a reimplementation of one of the Microsoft Silverlight demos using SVG and Javascript. It may be slightly slow but I think many people will be surprised that this level of interactivity can be accomplished on a web page.
After you are done playing with the above take a look at the SVG video demo. It is basically the same demo as above but has movies playing instead of static pictures. Unless you run a development version of Firefox you’ll just have to watch the videos.