jPlayer is the completely free and open source (GPL/MIT) media library written in JavaScript. A jQuery plugin, jPlayer allows you to rapidly weave cross platform audio and video into your web pages.

dotjs is a Google Chrome extension that executes JavaScript files in ~/.js based on their filename.

Fast, flexible, and lean implementation of core jQuery designed specifically for the server.

Zepto.js is a minimalist JavaScript framework for modern web browsers*, with a jQuery-compatible syntax.

The goal: a 5-10k library that handles most basic drudge work with a nice API so you can concentrate on getting stuff done.

Zepto's primary focus is on mobile devices, where small file sizes and tapping into the latest browser features matter most for fast loading and optimal runtime performance.

Turns out that pushing jQuery to the footer is quite easy for the common case. If all we want is a nice $.ready function that we have accessible everywhere we can explicitly define it without jQuery. Then we can pass the functions we capture to jQuery later on after it loads.

A javascript implementation of the W3C DOM.

Pronounced "geo" or "jQuery geo", this open-source project from Applied Geographics provides a streamlined API for a large percentage of your online mapping needs. Whether you just want to display a map on a wep page as quickly as possible or you are a more advanced GIS user, $.geo can help!

Annotator is a web annotation system. Loaded into a webpage, it provides the user with tools to annotate text (and other elements) in the page.

A little module that makes scraping websites a little easier. Uses node.js and jQuery.

Data Tables - sortable, filterable javascript tables: thanks for the tip @smashingmag, saved me like 10 hrs!

A list of scraping tools and resources which will make your life MUCH easier the next time you need some information from a crufty old website.

pjax loads html from your server into the current page without a full page load. It's ajax with real permalinks, page titles, and a working back button that fully degrades.

Aristo is a beautiful theme for jQuery UI that emulates the elegant style of the Cappuccino JavaScript framework.

Layout modes: Intelligent, dynamic layouts that can’t be achieved with CSS alone.

Filtering: Hide and reveal item elements easily with jQuery selectors.

Sorting: Re-order item elements with sorting. Sorting data can be extracted from just about anything.

By working with server-side Javascript (in this case node.js) developers can use widely accepted and battle-hardened libraries such as jQuery on the server thanks to jsdom, a server-side implementation of the DOM apis.

A unified user interface system across all popular mobile device platforms, built on the rock-solid jQuery and jQuery UI foundation. Its lightweight code is built with progressive enhancement, and has a flexible, easily themeable design.

It's well known that Google hosts several popular javascript libraries on their public CDN. A lesser know fact is that google also hosts an number CSS themes for jQuery UI (both v1.7.3 and v1.8.7). For whatever this remains undocumented. In the past, I've had a hard time finding them, so I decided to help myself out (and maybe others) and put a list together.

Chronos Timeline is designed specifically for needs in the humanities and social sciences to represent time-based data. Chronos allows scholars and students to dynamically present historical data in a flexible online environment. Switching easily between vertical and horizontal orientations, researchers can quickly scan large number of events, highlight and filter events based on subject matter or tags, and recontextualize historical data.

An easy way of making inlines orderable using drag-and-drop, using jQuery UI's sortable() plugin.