I recently downloaded the examples from the nightly build files and deployed the sandbox.war.
In this webapp you will find three AJAX examples – have a look at it, it looks very interesting!
Never heard from AJAX? Well, it is quite new, the originating article was written february 2005.
This technology is beeing adopted by many groups in the java community: myfaces is providing some components (see the sandbox example war) and struts shale is providing the backend (see topic remoting).
The original article can be found here:
Further reading to AJAX can be found in Wikipedia: