Sheldon J. Pacotti has created a toolset for teaching game development, especially for “constructing non-linear stories, which in my mind comprise more than talk trees and branching conversations.”
The toolset is build on Byob (which is based on Scratch).
Pacotti explains Game Blocks on video:
Download and tutorials available at: http://www.newlifeinteractive.com/main/index.php?option=com_content&view=category&id=40:cell&Itemid=60&layout=default.
Petri Lankoski 