jQuery Google Analytics Custom Events : jQuery GACE is a plugin for tracking custom events in your web page. It provides a simple wrapper for some custom elements.
Handsontable : Handsontable is a minimalistic approach to Excel-like table editor in HTML & jQuery. Now with column and row headers!
hoverIntent jQuery Plug-in : hoverIntent is a plug-in that attempts to determine the user's intent... like a crystal ball, only with mouse movement! It is similar to jQuery's hove...
Morris.js : Morris.js is a lightweight library that uses jQuery and Raphaël to make drawing time-series graphs easy.
jQuery TextExt Plugin : TextExt is a plugin for jQuery which is designed to provide functionality such as tag input and autocomplete.