A formal dance where Dad's go with their 'faithful' daughters, for the latter to pledge to preserve her virtue until marriage or when necessary.
Wayne: Hey lindsay, will you be attending the ball?
Lindsey: what ball?
Wayne: Purity ball of coarse, o I forget I just broke your virginity accidentally.
a creepy, covertly incestuous ritual in which a girl "gives" her virginity to her father who will "give" it to her husband on her wedding day. inherently misogynist, since no one seems to care about what boys do with their dingalings. usually put on by evangelical fundie Christian dads who "date" their daughters, exhibit lots of family love, and have an unhealthy interest in their daughters' sexuality.
Did you see the Glamour article on incest-fest... er, I mean, purity balls?