Prison of the Dead (2000)

Kristof, an eccentric rich kid, tricks his high school friends into getting back together for a reunion of sorts, under the pretense of a funeral. The group of twenty-somethings is forced to spend the night in an old abandoned witches' prison. During a Ouija Board séance, the schoolmates accidentally unearth three dead executioners from their graves. A little confused, and quite a bit angry, the Crypt Keepers initiate a killing spree that will only end when everyone is dead. Fortunately, the schoolmates all wore black. Too bad it's for their own funerals...