Mikes Modal Library is a javascript library to work and behave much like Facebook's Photo viewing experience. Clicking an individual photo will bring up the photo gallery window. It is designed to be used on social networking sites where a photo is on the left and some content is meant for the right side. The image scales to the largest size possible while still fiting in your monitors resultion.  

jQuery.localScroll will animate a regular anchor navigation. It will allow your visitors to navigate your site with a smooth scrolling effect.   Each time a link is clicked, the element you decide(can be the whole screen), will gradually scroll to the targeted element, instead of "jumping" as it'd normally do.  

Highlight.js is a syntax highlighter written in JavaScript. It works in the browser as well as on the server. It works with pretty much any markup, doesn't depend on any framework and has automatic language detection.   Highlight.js - Features: 92 languages and 49 styles (live demo) automatic language detection multi-language code highlighting available for node.js works with any markup compatible with any js framework  

interact.js is a standalone javascript module for handling single-pointer and multi-touch drags and gestures with powerful options such as inertia and snapping to grids or custom coordintes.   interact.js - Features: inertia snapping to a grid, custom anchors or paths. cross browser and device, supporting {Chrome,Firefox,Opera}' '{mobile,desktop}', ' and Internet Explorer 8+ interaction with SVG elements being standalone (not yet another jQuery plugin) introducing 0 additional DOM elemen

rlightbox is a jQuery UI mediabox that can display many types of content such as images, YouTube and Vimeo videos. It has many unique features like Panorama and Live Re-size. Like other jQuery UI widgets, it is ThemeRoller ready.   rlightbox - Features: Sets Set is a group of images, Youtube, Vimeo, or Flash swf videos, or a mix of them all. There may be many sets on a page and elements belonging to a set does not have to be put one after another in a container. YouTube support rlightbox

jQuery ReSmenu is a very simple and lightweight (~1Kb) jQuery plugin that collapse <ul> menus into <select> on responsive layouts.  

jQuery Flip-Quote creates a pull-quote from a text quote found in the document and flips to reveal the quote once it's scrolled into view. It also has a click feature that scrolls into and highlights the quote origin on the document. The plugin optimizes CSS 3D transform and other CSS3 properties to give it a 3D depth and perspective. This has been tested on all modern browsers, for IE and older browsers the plugin also has a fallback support.  

jQuery URLive lets you easily create a live preview of any url base on its Open Graph properties and other details, similar to Facebook's post attachment.  It doesn't only work on a <textarea> or <input> it also works on <a> tag and any element with a URL on its content. It's pretty lightweight as data fetching is done asynchronously via AJAX. It also doesn't require any back-end or PHP file to crawl and get the data as it uses YQL to query and make request on other domains.  

Quovolver is a jQuery plugin for revolving multiple testimonials or quotes in your document. Although, it can also be used to cycle through any group of elements. It is a great way to display quotes, testimonials or comments on your site.  

slideToucher is a touch enabled jQuery plugin for content swiping. Supports vertical and horizontal swipes.