Meteora is set of cross-browser widgets and controls for quickly creating rich and customizable web applications without programming excessive JavaScript that is painful to debug in every browser.

Meteora is based on the great mootools framework (version 1.11) and scripts that already work with mootools can be used with Meteora too!
To see some nice demos of this JavaScript widget library, check:
Requirements: No Requirements
Compatibility: All Major Browsers
mooSocialize is an ajax based social bookmark widget which helps submitting content to the social bookmark websites easily.
Once clicked, a window with the social bookmark website logos appears. Clicking the desired social bookmarking website does not redirect you to another website, a hovered window like Lightbox opens and the new website runs there. This nice feature helps keeping your website visitor on your page.

There is also a Wordpress plugin which helps integrating mooSocialize into a Wordpress powered blog.
Name says it all but mooSocialize is built with the beautiful mootools javascript framework.
Compatibility: All Major Browsers
Creating ajax applications are now much easier with WaveMaker Visual Ajax Studio for both developers and users with even no JavaScript experience.
WaveMaker Visual Ajax Studio is a visual builder that helps ceating web-applications using Ajax widgets, web services and databases. Best of all, it does not require complex codes, forms, patterns or portal frameworks.

Some Features:
- Drag & Drop Assembly
- LiveLayout™
- Push to Deploy™: One-touch application deployment
- Visual Data Binding>
- SOAP, REST and RSS web services
- Leverage existing CSS, HTML and Java
- Deploys a standard Java .war file