There are great many explorations on a decentralized protocols (this, Zeronet, IPFS, urbit) but I don't see many infrastructure related projects that we can play with today. Anyone can knows of hardware stack that enables fault-tolerant meshnets?
That would allow for real world use without having to rely on things like "pinning".
GPG encrypted messages with a huge list of fallbacks where messages got stored. (Pastes, private subreddit, Facebook via RSS).
The code was truly awful, but the premise was we just needed each others public keys, and all was good. (Killed the project when one of us lost their private key, and we realized hardcoding the public keys had been a terrible idea).
I don't think I have the code anymore, but shouldn't be much more than a weekend project if you stick with text only.