A ton of CSS, jQuery, and JavaScript responsive navigation examples, demos, and tutorials from all over the web. :
http://navnav.co/
responsive menu code library:
jquery-rocker A jQuery plugin for responsive menus
https://github.com/cvalleskey/jquery-rocker
Responsive Multi-Level Menu, Space-saving drop-down menu with subtle effects
http://tympanus.net/Development/ResponsiveMultiLevelMenu/index.html