FON are building a worldwide network of Wi-fi hotspots, based on individuals who share their connection. The idea is very simple: People put a router with FON's software and can decide if they want to (a) Share their connection in exchange for free wi-fi elsewhere (b) Share their connection and get paid.
Here's Martin's brief preach on why Capitalism and Socialism are needed together to push new community projects like this one. Besides the nice moral value, it definitely seems this dichotomy carries a good viral factor.
And I also liked their logo design - cheeky rebel flava :)