Cyclotron is a simple jQuery plugin for dragging 360° panoramas (cylindrical projection) and other seamlessly looping images around.
HTML5 Sortable is a jQuery plugin to create sortable lists and grids using native HTML5 drag and drop API.
Nestable is an interactive hierarchical list. You can drag & drop to rearrange the order. It even works well on touch-screens.
Overscroll is a jQuery plug-in that mimics the iphone/ipad scrolling experience in a browser. The plug-in adds a draggable drift to overflowed DOM elements as well as a set of fading 'thumbs'. OverScroll runs best on Safari 5+, Chrome 5+, and Firefox 3+ but should run just fine on most modern browsers.
TableDnD is a jQuery plugin that simply adds drag & drop functionality to tables.
This TableDnD plugin allows the user to reorder rows within a table, for example if they represent an ordered list . Individual rows can be marked as non-draggable and/or non-droppable. Rows can have as many cells as necessary and the cells can contain form elements.
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)