TCVN Categories Treeview is a great module of Joomla. It's allows display K2 categories in a tree view, like a file explorer. This is useful for using K2 as business directory or any listing type. This module works great with Joomla 2.5.x and K2 version 2.x.x. You can run multiple TCVN Categories Treeview for K2 on a single page with much more options via module parameters.