NIMTUG’s Damien McGivern has been building an AJAX library for use with ASP.NET.
If you don’t know what AJAX is, you’ve probably experienced it at some point when visiting a particularly interactive web site and thought “wow, that’s cool.. how’d they do that?!”
AJAX combines a number of technolgies to make it easy to author responsive web pages by changing the postback model (here’s the Wikipedia description and a great explanation of Ajax).
Damien has posted his ASP.NET AJAX libary and some demos, and you can find out more through his blog.