Superfly is a responsive WordPress menu plugin that generates space efficient vertical push/sliding/static navigation, icon toolbar or fullscreen menu on your choice. Superfly makes navigation much easier and user-friendly both on desktops and mobiles. Concept of off-canvas vertical menu that proved itself on mobiles now shines on desktops too! It can be used as always visible navigation as well.

Demo: http://codecanyon.net/item/superfly-responsive-wordpress-menu-plugin/8012790