The people behind mootools have put together a speed/validity test to compare the speed of CSS3 selectors in the most popular javascript libraries. Great job, but too bad to find out that jQuery is at the slower part of the line up...
markItUp! is a JavaScript plugin built on the jQuery library. It allows you to turn any textarea into a markup editor. Html, Textile, Wiki Syntax, Markdown, BBcode or even your own Markup system can be easily implemented.
Awesome Box is a YUI alternative to Lightbox2. It's similar to Lokesh Dhakar's project Lightbox 2, using the Yahoo! UI Javascript Library instead of Script.aculo.us
A multi-author weblog with the aim of sharing information about the Jquery JavaScript library. Each entry is placed in categories according to level of difficulty.
Interface is a collection of plugins for jQuery java script library. With this plugins you can build Web 2.0 aplications with the same same simplicty as using jQuery and provide a rich user interface.
The Json.NET library makes working with JavaScript and JSON formatted data in .NET simple. Quickly read and write JSON using the JsonReader and JsonWriter or serialize your .NET objects with a single method call using the JsonSerializer.
Mapstraction provides a common API for various javascript mapping APIs to enable switching. Developers can code their applications once, and then easily switch mapping provider based on project needs, terms and conditions, and new functionality.