Street game design is a different thing to formal game theory. But both look like fun!
Stanford University are running an online class on Game Theory. Apart from being online, this is a "real" class, with weekly lectures, tutorials, assignments and a four-hour exam.
They encourage people to get together to watch the lectures and discuss the material (but not the assignments). Let's set up a study group!
Details are at:
http://www.coursera.org/gametheory
(image by Pieter Brugel)