Nice tutorial about creating an AJAX file upload form, that will let visitors upload files from their browsers with drag/drop or by selecting them individually.
jCarousel is a jQuery plugin for controlling a list of items in horizontal or vertical order. It provides a full-featured and flexible toolset for navigating any HTML based content in a carousel-like fashion.
Ajax Autocomplete for jQuery allows you to easily create autocomplete/autosuggest boxes for text input fields.
Built with focus on performance - results for every query are cached and pulled from local cache for the same repeating query. If there are no results for particular query it stops sending requests to the server for other queries with the same root.
The jQuery BlockUI Plugin lets you simulate synchronous behavior when using AJAX, without locking the browser. When activated, it will prevent user activity with the page (or part of the page) until it is deactivated.
BlockUI adds elements to the DOM to give it both the appearance and behavior of blocking user interaction.
The jQuery Form Plugin allows you to easily and unobtrusively upgrade HTML forms to use AJAX. The main methods, ajaxForm and ajaxSubmit, gather information from the form element to determine how to manage the submit process. Both of these methods support numerous options which allows you to have full control over how the data is submitted.
jQuery Gantt Chart is a simple chart that implements gantt functionality as a jQuery plugin. Plugin uses AJAX to retrive JSON data and render them as Gantt chart with many features such as zooming or paging.
FullCalendar is a jQuery plugin that provides a full-sized, drag & drop calendar like the one below. It uses AJAX to fetch events on-the-fly for each month and is easily configured to use your own feed format (an extension is provided for Google Calendar). It is visually customizable and exposes hooks for user-triggered events (like clicking or dragging an event)