I recently presented a paper at ICSIT 2012 - The 3rd International Conferenece on Society and Information Technologies called "Completing the Experience: Debriefing in Experiential Educational Games".
I talk about the concern in creating experiential learning games designed to be used in informal learning. One of John Dewey's theories about learning is that education is the combination of experience and reflection upon that experience.
If a game provides only the experience without the reflection, then it isn't as effective in providing education. In a classroom, the teacher can provide that reflection process for students. Outside of the classroom, if the game does not facilitate the reflection or debriefing, then the opportunity to learn is lost.
In this paper, I present the theories behind this idea, discuss several models for debriefing, and then talk through a number of ways that game designers could incorporate debriefing activities into their educational games.
You can see the preprint of this paper at http://scottnicholson.com/pubs/completingexperience.pdf