What is "nagelbalken"

Wettnageln or Nagelbalken (German for competitive nailing) is a sport in which participants compete against each other to drive nails into a wooden plank or shape.

Craftsmen in German-speaking countries have driven nails into certain wooden shapes for luck for centuries, as in the case of the Stock im Eisen in Vienna. The use of this to a popular contest of skill is known since the First World War, during which it was introduced as a means of gathering donations for war-time charities, in the form of Nail Men. The current use is just for leisure and as a game at events and festivals, often for children and as a wedding custom.