For JavaScript and AJAX applications, Taffy DB is a beautiful tool.

Taffy DB is an open source JavaScript library that acts as a data layer inside the applications. Just think of it as a SQL database in your web browser.

Let’s say you have a collection of products and you want to find every product that costs less than $10 and is not a book. Simple, just write some JavaScript:
products.find({price:{lessthan:10},
type:{not:"Book"}});

Major features:

• Under 10K!
• Simple, JavaScript Centric Syntax
• Fast
• Easy to include in any web application
• Compatible with major Ajax libraries: YUI, JQuery, Dojo, Prototype, EXT, etc
• CRUD Interface (Create, Read, Update, Delete)
• Sorting
• Looping
• Advanced Queries

Check out the Getting Started Guide for Taffy DB‘s capabilities.

Smoot is a tool, developed with xajax and Pear::DB for creating diagrams of icons and links between them.

Features include Google Maps and Google Earth integration, configurable tool palettes, and automated palette generation from a Google local query.

Smoot builds relations between objects with mouse clicks and the result can be stored easily. This nice tool can be a starting or an inspiration point for many projects like "online heritage services", "online diagram services" and much more.

Easy News is a jQuery plugin which allows creating "news slides" on the fly.

Supporting any HTML content, and even Flash, it can display the content with fade-in / out, left to right ,slide-up / down effects.

Using this jQuery news slide plugin you can adjust the speed of the effects and rotation, or enable / disable mouse-over pause features.

Easy News, has also a "plus" version which displays content with another sliding effect and can be integrated into Joomla with a ready to use module.

Online image cropping is a widely used feature in web applications.

Prototype JavaScript Image Cropper UI is an unobtrusive script based on Prototype and script.aculo.us.

It allows you to select any area in an image and gives the x, y, x1, y1, width and height values which are enough for a succesful image cropping.

This Prototype image crop UI also has ratio locking, selected area preview and minimum height – width options.

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.

Datetime Toolbocks is a JavaScript library with advanced date parsing that generates date data from the text passed. A simple example would be "today", "next friday", or "last monday".

This smart date parsing JavaScript library also has a DHTML based date selector which makes the library vey functional for users who would prefer text or visual input selection.

DateTime Toolbocks currently supports Ruby on Rails as the development platform.

SearchField is a lightweight and unobtrusive script that adds styling and static auto-suggest behaviour to your search form fields.

Auto-suggest data comes from a static data source, a JavaScript file, no data connections are necessary, updating the JavaScript with the common phrases is enough.

To use SearchField, all you need is linking to the CSS and JavaScript files, that’s all.

Sphinx is a standalone search engine application that can be integrated with your data sources to provide fast, size-efficient and relevant fulltext search functions.

To clear how powerful it is, Sphinx is already used in BlogCatalog, Joomla & phpBB community forums and more.

Sphinx currently supports:

• MySQL
• PostgreSQL
• XML Pipe mechanism that allows indexing of XML data

Some features of Sphinx:

• high indexing speed (up to 10 MB/sec on modern CPUs)
• high search speed (avg query is under 0.1 sec on 2-4 GB text collections)
• high scalability (up to 100 GB of text, upto 100 M documents on a single CPU)
• supports distributed searching (since v.0.9.6)
• supports phrase proximity ranking, providing good relevance
• supports any number of document fields (weights can be changed on the fly)
• supports different search modes ("match all", "match phrase" and "match any" as of v.0.9.5)

Gaia is a front-end Flash framework for AS2 and AS3 and is designed to dramatically reduce development time.

It provides solutions to the challenges and repeated tasks faced with front-end Flash site development, such as navigation, transitions, preloading, asset management, site structure and deep linking.

There is a nice screencast here.

Gaia’s unique event hijacking engine enables you to achieve some really complex behavior with very little code. Additionally, Gaia has scaffolding which generates all the base files for your site, including Flash files, class files, and even exclude.xml files!

It uses SWFObject and SWFAddress and also forces applications to support deep linking (great for SEO purposes).

If you’re developing Flash sites and want to speed up your Flash workflow with rapid development and don’t want to have to learn a complicated framework API, give Gaia a test drive.

Radiant is an open source content management system built with Ruby on Rails. It is built for small developer teams other than the end-users as it requires programming knowledge.

With a very simple interface, Radiant offers flexibility when creating the design & content. 3 parts: pages, snippets (like PHP includes) and layouts create the core of the system.

It offers a flexible site structure where pages can be arranged according to any hierarcy.

Radiant has a custom template language named Radius (similar to HTML) which can be used inside pages, layouts to include content from other pages or display content conditionally & more. It also has an intelligent caching mechanism which helps serving pages faster while ensuring the content is up-to-date.