Creating multi-columns sub-menus (a.k.a mega-menus) using Superfish module is pretty easy.
Step 1: Enable "multi-column sub-menus" in your block settings.
Step 2: The structure of the sub-menu has to be slightly altered. Take the following as an example:
In order to display the children menus in two columns all you need to do is to add 2 extra menu items and place those children menus under them:
This module implements the jQuery plugin called Superfish [1] on Drupal menus. It provides Drupal users the ability to add some "splash" to Drupal menus with very little effort.
