conkers

thumb|The game of conkers is played with a horse-chestnut seed with a string threaded through it.

Conkers is a traditional children's game in Great Britain and Ireland played using the seeds of horse chestnut trees—the name 'conker' is also applied to the seed and to the tree itself. The game is played by two players, each with a conker threaded onto a piece of string: they take turns striking each other's conker until one breaks.