"A few years ago I attended my first conference with an alternate reality game implemented as a way of engaging participants as a learning community, and ever since I’ve been hooked. Amanda Visconti and I ran several conference games at THATCamps involving escaped video game characters and invading aliens. Alternate Reality Games (or ARGs) are built on the idea of a shared story invading the physical world, and can include scenarios of invading aliens, impending apocalypse, or mysteries waiting to be solved."
http://www.chronicle.com/blogs/profhacker/alternate-reality-games-in-the-classroom/54769