CodeCanyon - PBK Mega Menu for Wordpress | 770 KB
PBK Mega Menu Plugin for Wordpress is your easy way to add a functional and customizable Mega Menu to your Wordpress website. Adding menu items and content is just like adding posts or pages... If you know how to use Wordpress, then you already know how to use the Mega Menu plugin.
Built in shortcodes give you flexibility when laying out your dropdown content, and a plugin options page allows you to choose from 6 different color options. If you're down with CSS, you can style the menu to your heart's delight by uploading a file named "“userdefined-mega-menu.css" with your custom styles in the same directory as your theme's primary stylesheet.
DEMO:
http://codecanyon.net/item/pbk-mega-menu-for-wordpress/147559