Yesterday I joined Hyperboria.
Hyperboria is a decentralized network established with the principles of freedom and security at its core.
To get into Hyperboria you have to install CJDNS which and then get on IRC and find someone that is willing to give you a password to connect through their computer. Ideally, you'll peer with multiple people so you have a more reliable connection to the network. If you only have one peer and their computer goes down, so does your connection.
I'll be honest. As of right now, I haven't found a lot of use from being in Hyperboria. There are a few websites I've found that are only accessible through Hyperboria which are reasonably cool. One is socialno.de which is a sort of Twitter clone. There is also hyperboria.name which is an e-mail service.
If you try to click on either of those links you probably won't get a website. That's because you have to be connected to Hyperboria in order to access them.
The Hyperboria network is part of an international effort to protect free speech, called Project Meshnet.
It's a fun experiment to visit these websites and be a part of this community. It requires some degree of technical savvy to get on Hyperboria so the community you find in there is very smart and interesting. If you have some time and interest, it's worth trying out.
UPDATE: I'm no longer on hyperboria. I found it difficult to keep the software working and up to date and so when it eventually broke I just deleted it and haven't been back on.