Go is a very ancient game about creating territory. Go is played on a board with intersections formed by evenly spaced lines. One player plays the black stones, the other player plays the white stones. The players take turns placing one stone at an intersection. The object of the game is to make territory by surrounding vacant intersection points. There are ways to break up your opponent's attempt to make territory. For each turn you need to decide whether to use your stone to create territory for yourself or to use your stone to disturb your opponent's territory. The color that has surrounded the greater number of vacant intersection points is the winner.
In the movie "A Beautiful Mind" mathematician John Nash is challenged to play the game by a fellow graduate student. It is his first time playing the game. He does surprisingly well but loses. He then points out how the game is mathematically flawed.