What is "unspunnenfest"

Unspunnenfest is a festival held in the town of Interlaken, Switzerland, near the old ruin of Unspunnen Castle, in the Bernese Alps, approximately once every twelve years, most recently in 2006. The festival highlights traditional Swiss culture and features competitions of Steinstossen (stone throwing), Schwingen (wrestling) and yodeling. The stone throwing competition uses an stone known as the Unspunnenstein ("Unspunnen Stone"), made of Aare granite from the Hasli valley.