The AJAX Control Toolkit is a joint project between the community and Microsoft. Built upon the ASP.NET 2.0 AJAX Extensions, the Toolkit aims to be the biggest and best collection of web-client components available.

The Toolkit addresses three needs. First it gives website developers a place to get components to make their web applications spring to life, second it gives a set of great examples for those wishing to write client-side code, and third it is a place for the best script developers to get their work highlighted.

All of the controls in the Toolkit are built upon a set of classes that really help streamline the process of writing control extenders. These classes form a thin “glue” layer between the Toolkit controls and the ASP.NET AJAX classes as they exist today. While the AJAX Control Toolkit is focused primarily on providing great AJAX controls and extenders, it also includes a powerful animation framework which you can use to add awesome visual effects on your pages.

Requirements: -
Demo: http://asp.net/AJAX/AjaxControlToolkit/Samples/Default.aspx
License: Microsoft Public License