The AJAX Engine
This implementation has its focus on building an AJAX Engine and Web Controls upon standard WebServices (SOAP, WSDL) on the web server instead of using a new or proprietary protocol. The benefit for that is that there is no special coding necessary for most parts of the networking infrastructure and that many aspects like caching and security of the WebService implementation can be reused.
Atlas is a free framework for building a new generation of richer, more interactive, highly personalized standards based Web applications. This new Web development technology from Microsoft integrates client script libraries with the ASP.NET 2.0 server-based development framework. In addition, Atlas offers you the same type of development platform for client-based Web pages that ASP.NET offers for server-based pages.
MonoRail (former Castle on Rails) is a MVC web framework inspired on Action Pack. The Action Pack way of development is extremely productive, very intuitive and easily testable
MochiKit.Visual provides visual effects and support functions for visuals.
Anthem.NET is a free, cross-browser AJAX toolkit for the ASP.NET development environment that works with both ASP.NET 1.1 and 2.0.
AJAX Toolbox – AjaxRequest
A small library for making dynamic HTML programming easy and fun.
Some open ajax librabries
Here is another version of GreyBox.
GreyBox – Redux
ThickBox – One box to rule them all..
AXAH (Asynchronous XHTML and HTTP) – Crawl before you AJAX
LightBox (** good for photo gallery)
Lightbox JS is a simple, unobtrusive script used to overlay images on the current page. It’s a snap to setup and works on all modern browsers