What is a conker? It's the fruit of a horse chestnut tree - hard, brown, half-dollar sized orbs. The trick is to pick the good ones, drill a hole through their center, hang them on a knotted shoelace and your conker is good to go. Two players take alternating whacks at the other's chestnut until one shattered.
Although the game is discouraged in school, the World Conker Championship is held every year in Northamptonshire.
What to know how to win? Enjoy this informational video How to Win at Conkers