This tutorial details how to create a custom feature that will utilize RokBox to present a module position inside a modal popup box that will be triggered by a link/button on the frontend. For this tutorial we will be making a login module popup.
NOTE: The login popup functionality requires the RokBox System Plugin to be installed on your site. Before beginning, please ensure that you have downloaded and installed the latest version of RokBox.
> more > http://www.gantry-framework.org/documentation/joomla/tutorials/creating-a-popup-login