“In 1518, one of the strangest epidemics in recorded history struck the city of Strasbourg. Hundreds of people were seized by an irresistible urge to dance, hop and leap into the air. In houses, halls and public spaces, as fear paralyzed the city and the members of the elite despaired, the dancing continued with mindless intensity. Seldom pausing to eat, drink or rest, many of them danced for days or even weeks. And before long, the chronicles agree, dozens were dying from exhaustion. What was it that could have impelled as many as 400 people to dance, in some cases to death?”
See also: choreomania, the Tanganyika laughter epidemic of 1962 (the wonderful Radiolab did a segment last year about this), la danse macabre, and St. Vitus’ Dance, not to mention the final scenes of Bergman’s The Seventh Seal and Fellini’s 8½.
(Via NCBI ROFL)