AIDS (AJAX Image Dump System) is a simple, yet powerful AJAX-based image host system. It's geared toward forum usage, and it generates bb-code for cutting and pasting into forums that support bb-code. It lets people create user accounts to keep track of their pictures, reaccess them later to view stats, delete them, or simply copy the bb-code again.
AJAX Tree Control is a modified version of SilverStripe's tree control. It adds dynamic loading of child nodes via AJAX. The default implementation uses the prototype library to make dynamic requests, but this behavior can be overridden by setting functions on the global Tree object. There are a few demo Ruby on Rails applications included in the distribution that show how to use and customize the tree.
APIlity Agua is an AJAX application that allows users to manage their Google AdWords accounts in an interactive and asynchronous way. The application behaves almost like a program on your desktop, but runs entirely in your Web browser. The name Agua stands for APIlity GUI for AdWords.
ARSCIF is a powerful framework that makes it trivial to use asynchronous remote-script callback invocation (AJAX) techniques. It helps the developer by working out problems such as data and character encoding, concurrency control, browser implementations, and so on, allowing the creation of pages with sophisticated, dynamic features.