Apparently each year they (and other Pennsylvania Dutch folk festivals) re-enact the hanging of this poor serving girl who was seduced by a neighbor, becoming pregnant ("the luckless girl, perhaps from the very simplicity of her disposition too easy a prey to the wiles of the designer, was led aside from the path of virtue, and confronted with the consequences of her error"). In fear and confusion, the poor girl hid her condition, then killed the baby, and was executed for it.
Originally, I gather, it was reenacted as a moral lesson, but now the re-enactments are defended on the grounds that they are a tradition. So odd. Seems to me that watching a young girl hung in a fake gallows is a real great way to ruin an otherwise lovely day of listening to accordions and eating shoefly pie, especially as it's repeated three times a day, making it hard to miss. Humans are such strange creatures.