Tipsy is a jQuery plugin for creating a Facebook-like tooltips effect based on an anchor tag's title attribute.    

WikiUp is a jQuery plugin which gets Wikipedia descriptions in tooltips.    

FullCalendar is a jQuery plugin that provides a full-sized, drag & drop calendar. 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).     

sBubble is a jQuery tooltip plugin which is totally based on CSS3 for shapes and animations. There are no images used and no jQuery code used for animation. Plus some color themes are also provided.    

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.     

Scrolltab is a jQuery plugin that adds tabs visually associated to their position relative to the scroll bar. This enables a developer to attach floating tabs to the scrollbar of the brwoser that will scroll the user to the position indicated by the tab. This tab is expandable with content within.    

Easy responsive tabs is a lightweight jQuery plugin which optimizes normal horizontal or vertical tabs to accordion on multi devices like: web, tablets, Mobile (IPad & IPhone). This plugin adapts the screen size and changes its action accordingly. Easy responsive tabs - Features: Horizontal / Vertical Tabs to Accordion Tabs and accordion are created entirely with jQuery Supports multiple sets of tabs on same page Cross browser compatibility (IE7+, Chrome, Firefox, Safari and Opera) Mu

DTooltip is designed to be flexible and still very simple to use.    DTooltip - Features: Style the tooltip with pure CSS. Supports HTML in the tooltip. Works nicely in IE8+. Automatic handling of the psuedo elements creating the arrows.    

The Lucid Tabs jQuery plugin allows you to create tabs and corresponding pages with minimal markup and not a lot of JavaScript.    

Validetta is jQuery plugin which you can do client-side validation of your forms. It aims to decrease your burden with easy usage and flexible structure.    Validetta - Features: You can check fields whether it is empty or not or it is chosen or not. You can do e-mail check. You can do number check. You can check if the two fields are equal to each other. You can check credit card number validation. You can limit number of characters written to fields. You can limit number of choice of