jQuery DynoMenu Plugin
Dynomenu is a CSS3 based dropdown menu as coded by Red here: http://www.red-team-design.com/wp-content/uploads/2011/03/css3-dropdown-menu-demo.html. The plugin will adjust the contents of the menu based on the width of the menu and its contents - it will make the font smaller and/or add a new menu item 'more' which will contain the items that do not fit.