ASP.NET “Atlas” is a package of new Web development technologies that integrates an extensive set of client script libraries with the rich, server-based development platform of ASP.NET 2.0. “Atlas” enables you to develop Web applications that can update data on a Web page by making direct calls to a Web server — without needing to round trip the page. With “Atlas”, you can take advantage of the best of ASP.NET and server-side code while doing much of the work in the browser, enabling a richer user experience.
Go to http://beta.asp.net/default.aspx?tabindex=7&tabid=47 to get it and try it!
Note this site is also the ASP.NET 2.0 beta site....