I've had this paper and demo floating around for a while now, and have just got around to posting it. This is a video of some work a student of mine performed linking a game mod to the YAWL workflow engine developed by QUT.
The grey user interface, spawning of enemies and registration of killings is coordinated by the YAWL workflow tool, developed at QUT, Brisbane, Australia - http://www.yawlfoundation.org/
This shows how easy it is to give a 3D interface to workflow systems, and shows a very simple example of how to control the "Narrative" of a virtual environment by using workflow systems. In the end, a game quest is just a form of goal directed workflow, so I decided to test it out, and the video is the result.
Has been written up as a conference paper at: http://eprints.qut.edu.au/archive/00012712/