Surely you remember the weird stuff you did at sleepovers and slumber parties when you were a kid. Did you use a ouija board to find out who you would marry? Did you ever try to levitate someone? Or repeat "bloody Mary" three times in front of a mirror? These activities are most often enjoyed by adolescents and younger teenagers, during a time when they are exploring adult things, like fortunetelling and parlor games that border on occult practices, along with discussions of puberty and sex. I recall my friends trying to recreate a seance, even though no one knew what that was supposed to look like. I remember getting scared silly a few times, and even more so those times I scared everyone else. It's all a matter of setting the mood and getting everyone to go along. PBS invited a bunch of adults to a slumber party to recreate those rituals in case you need a reminder, explain how they work, and let us in on the origins of these games we use to horrify each other.