okayNav is a jQuery plugin to create responsive navigation that aims at progressively collapsing navigation links into an off-screen navigation instead of doing it for all the links at the same time
Multi-Device Scrolling Menu is a simple responsive horizontal menu ready for any device.
megamenu.js is a responsive, cross-browser, jQuery mega menu.
An open-mobile-menu hamburger that turns into close-mobile-menu button with a not-the-same-as-always animation but a quite discreet another one.
Stretchy Navigation is a rounded navigation trigger that stretches on click/tap to reveal the navigation items.
A tutorial about creating a simple multi-level menu with delayed item animations and an optional breadcrumb navigation and back button.
GreedyNav is a responsive navigation menu that stacks items into a dropdown menu when they overflow.
Dropit is a jQuery plugin for single level dropdown menu's. Just simple and flexible dropdown's in jQuery.
A template for a simple page stack navigation by using CSS and jQuery.
A tutorial about creating simple accordion menu with support for sub level items by using CSS and jQuery.
A framework for making responsive cross-browser overlay menus.
A nice tutorial about creating Responsive Sidebar Navigation. It's easy-to-integrate side, vertical navigation, ideal for dashboards and admin areas.