Kademlia is also quite fun to implement! It's a great example of a distributed system, and me and a couple of friends actually made our own in golang (https://g

Kademlia is also quite fun to implement! It's a great example of a distributed system, and me and a couple of friends actually made our own in golang (https://github.com/maxsnew/kademlia-go https://github.com/maxsnew/kademlia-go). We also decided to build a fault-tolerant, secure file store on top of it (https://github.com/jontonsoup/tin-foil-hat https://github.com/jontonsoup/tin-foil-hat), as an educational experience.