This site demonstrates the Mega Menu Plugin.
The menu on this site demonstrates some of the features.
You can read more about the plugin on its own siteMax Mega Menu – WordPress Mega Menu Plugin and read about the Features. We use the standard version of the plugin on Glow Blogs so do not support the pro features.
The mega menus are more accessible than some of the older theme menus and fix the problem with yoko theme menus on mobile.