I'm surprised that no-one's mentioned Freenet yet - it is effectively the decentralized internet that people are mentioning. The client allocates a certain portion of your disk (you specify this, default is 10GB) and then web data is stored on your machine. If someone wants to browse the site then it retrieves this data from the nearest peers.
there is no way id do that, you run huge risks of abuse and not to mention storing child porn. its another reason why id never run a tor node on my home connection. however i have considered getting an anonymous dedicated server somehow for tor.