A frieind introduced me to geocaching. This is another great example of an amazing organizing effort taking place without the usually economy. I guess somebody somewhere is making money on it, but most of the providers and consumers are just in it for the fun. Literally tens of thousands of geocaches now dot the globe, not beacuse somebody thought up a new way to to make money, rather because a community of gps owners found a new way to use their device.
Travel bugs are particularly interesting. You have an object (called a travel bug) and you give that object a 'tracking' number. Then you say that your 'bug' wants to get to Delaware. When users come across the bug, they will help it along it's way, even if it's just a few miles in the right direction. These travel bugs often travel the world. You could say it's like Fed-Ex, only not as fast, since it may take years to get to the right destination.
There are other variations on this 'game' that prove to be quite interesting.
As of today, there are 122304 active geocaches in 210 countries.