-- Each cell with one or less neighbors dies, as if by solitude
-- Each cell with four or more neighbors dies, as if by overpopulation
-- Each cell with two or 3 three neighbors survives
-- Each cell with three neighbors becomes populated
Conway's Game of Life is a zero player game that plays out on a 2-dimensional grid filled with active and non-active cells of equidistant size. The game progresses by looking at the current state of each cell, and deriving a new one from it according to the rules stated above.
This game is a type of cellular automation whereby cells in the grid are informed of the nature (state) of their environment and can make decisions based on that "knowledge" according to an a priori rule set without outside interference. The Game of Life is Turing complete, and can be used to derived any currently known Turing Machine.