Love Hultén, who makes retrofuturistic game consoles, built this thing called an EvoBoxx, which lets you play mathematician John Horton Conway's Game of Life, a cellular automaton he devised in 1970. "The game is a zero-player game," writes Hultén, "meaning that its evolution is determined by its initial state, requiring no further input. One interacts with the Game of Life by creating an initial configuration and observing how it evolves, or, for advanced players, by creating patterns with particular properties."
If you don't have an EvoBoxx, you can play The Game of Life here.
Image: Love Hultén