Wired has a neat little write-up on the Chaos Computer Club out of Germany (you'll want to follow the links therein).

The History of the Chaos Computer Club - Geekdad - Wired.com

With causes like ensuring secure voting machines, protecting privacy, defeating censorship and governmental obfuscation, and promoting hacker ethics, the CCC has become something of a hacktivist powerhouse. They hold an annual "Chaos Communications Congress" gathering and also a very cool hacker camp every four years. In 2007 the CCC camp coincided with Defcon 15 (the US's biggest hacker gathering) and a lot of people went to both on a special chartered flight, dubbed "Hackers on a Plane."