Javascript libraries for dealing with touch events, multitouch, normalizing across the Webkit/IE touch models, and all that jazz.
Note: these could use some categorization and better detail
Touchy - Highly configurable jQuery plugin. Exposes event data (velocity, etc) for longpress, drag, pinch, rotate, swipe. Example use cases: prevent conflict between drag and swipe; get pinch abstracted across Android and iOS; create a single finger rotation.
mootools-mobile - Wraps click handlers with touch and provides some custom events.
jquery.doubletap - Custom touch events for jQuery. Demo.
touch-layer - Custom events and gestures handler for touch enable mobile devices.
WKTouch - Hardware accelerated multi-touch drag, scale and rotate plugin for Mobile Webkit.
Hammer.js - A javascript library (only 2kb) for multi-touch gestures: Tap, Drag, Pinch, Hold
MagicTouch.js - Standards-compatible touch event polyfill to map trackpad touches to touch events. Uses NPAPI plugin.
Touchable - Unifies touch and mouse events
Touchy - Lightweight (no dependencies) multi-touch, models individual fingers
thumbsjs - from the PhoneGap team. Heavily tested on many devices. Mature.
YUI 3 touch abstraction - support for subscribing to native touch and gesture events
jQuery Mobile vmouse - from the jQuery Mobile team. Supports normalized handling of mouse and touch events under one event convention: vclick, vmousedown, vmouseup, vmousemove, etc.
interact - abstracted mouse and touch events into generic pointer events. Uses eve under the hood.
tap.js - A lightweight 'tap' event JavaScript plugin for mobile browsers (no dependencies)
tappable - A simple, standalone library to invoke the tap event for touch-friendly web browsers.
jsTouchLayer - A javascript based touch events library, agnostic of any javascript libraries.
dojo/touch - Dojo detection functions for touch events
jQuery UI Interactions - Rewrite of the existing jQuery UI interactions, now with mouse, touche and pointer (aka MSPointer) support. Work in progress, but draggable already works great for all three event APIs.
Ember-Touch - A lightweight library for building and using touch gestures with Ember Applications.
Jester - Easy JavaScript gesture recognition for iPhone and iPad.
Mobile-Web-based-Gesture-Recognition - Based on Dollar. Demo.
shake.js - A custom 'shake' event plugin for mobile web browsers using device accelerometer. (Okay, not strictly touch, but it does require you to use your hand :P)
dojox/gesture - Dojo detection functions for gesture events
phantom limb - make desktop browsers simulate touch events. with a big hand
Swipe JS - carousel (aka slider) component that is touch friendly
Swiper - mobile touch slider with hardware accelerated transitions
jQuery Mobile Pagination - touch-drag pagination between separate HTML documents or jQuery Mobile "pages"
wkslider - A touch–optimised UI range slider JavaScript plugin (no dependencies)