[Ajax] Check Out the "Atlas" Control Toolkit

You may want to look at the "Atlas" Control Toolkit site where they have a list of cool samples of what you can do with it, and it's dead simple. You can probably live without some of the controls, but some of them are quite useful and you would have to spend quite some time to achieve the effects you get for free. My favos on that list are the CollapsiblePanel and the TextBoxWatermark.

Some may argue that these controls have nothing to do with Ajax, but Ajax has become synonymous with a rich UI, and this is what "Atlas" gives you for sure.