Superfish - Suckerfish on 'roids. Note: there is now an official GitHub repository for Superfish.
Superfish is an enhanced Suckerfish-style menu jQuery plugin that takes an existing pure CSS drop-down menu (so it degrades gracefully without JavaScript) and adds the following much-sought-after enhancements: Supports touch devices. On Android, iOS, Windows Phone 7 and IE10 (with touchscreen), first touch will open an associated submenu, second will follow the link. Interface elements for jQuery - Documentation - FX. A collection of animated effects to be used on DOMelements extending the base effect collection of jQuery. example Pulsate The element fades in and out for several times. Often used as a pattern to demonstrate that an element has been modified (usually via Ajax). List of Useful jQuery Plugins: jQuery, JavaScript. Best jQuery Plugins all in one place.
BBQ: Back Button & Query Library Source: Leverages the HTML5 hashchange event to allow simple, yet powerful bookmarkable #hash history.