Take a look at this demo I’ve knocked up.
Wiggle the slider and see what happens. It’s a terrible learning object, but it’s just an exploration of how easy it is to set up using HTML, CSS and JavaScript. No, really! Look at the source code and there’s no flash or other plugins involved. It’ll work more slowly in IE than Firefox, but works in both, at least on Windows.
I’m using the Canvas tag, which is natively supported by Firefox and Safari. Thanks to the excanvas library provided by Google, adding canvas functionality to IE is really easy.
I know that SVG (scalable vector graphics) has many advantages over canvas, and may be the way things go in the future but canvas has the key advantage that you can use it right now in modern browsers without needing plugins.
Also, the way of working with canvas is reminiscent of the graphics commands of computers back in the early 1980s, which is a good thing to anyone who grew up with those computers.
The slider is part of the Yahoo User Interface (YUI) library and the animated text is a YUI animation motion.
Plugging the things together, and to other things on the page (e.g. the web form) just requires a bit of JavaScript. I’ve long wanted to be able to make interactive web pages this easily.