Wroclove.rb 2018 lightning talk explaining Ethereum as a distributed database that stores the same data on all computers and, unusually, stores code as well as data. Smart contracts are described as a set of functions plus some storage whose contents can only be mutated via those functions through signed transactions. Walks through how people use this to invent their own currencies (a mapping from addresses to token balances, with mint/transfer functions), points the audience to ethereum.org tutorials, and jokes that if you want to launch an ICO you should come to Belarus because it's legal there.