What about virutal economies? The study of the Everquest economy was amazing if you ask me.

http://news.bbc.co.uk/2/hi/science/nature/1899420.stm

Norrath, the setting for the online game Everquest, has been found to be the 77th richest country in the world, sandwiched between Russia and Bulgaria.

Research carried out in the United States shows that virtual internal markets, combined with illegal online trading on auction websites, mean that Norrath has a gross national product per capita of $2,266, bigger than China and India.

The virtual economies in these MMORPGs is also very interesting. The statistics about their estimated real world valuations are amazing. There probably are some lessons to be learned by studying them in detail, and in how they differ from games where virtual<->real world transactions are banned and where they are allowed and encouraged. I wonder if it's possible to work out a non-"capitalist" system that works in a game that can work in the real world.

For example, what if two virtual worlds for the same game (i.e. two separate servers where user information isn't shared between them) become connected, and the two worlds have significantly different economic values for goods and services. Somehow an equilibrium is reached, but how?