Cryptocurrency
I think about cryptocurrency quite a lot as I feel it is going to play an important role in humanity's future. As for the first time we have a currency in which anyone can be the mint and no one has to rely on the trust of a government or 3rd party. Money can be moved seamlessly and cheaply across borders without the control of governments. I think it will be a liberating tool for people who live under authoritarian regimes to have a sound financial system. I am also really interested in seeing how smart contracts are going to play a role in future governance. To me it would be really interesting to see a seastead essentially try to create a smart contract government where all the main functions of the government are handled by smart contracts. Allowing people to form companies, change their names, and get married in a matter of seconds cutting out bureaucracy.