Attention, Late Nite Catechism fans: Sister's back with a vengeance. Patricia Musker (alternating with Lynda Shadrake) brings her chop-busting A game to this spin-off of the long-running homage to old-school nunnery. Good material abounds in Sister's Golden Rule seminar, in which she scrutinizes cell phone yakking and modern assholiness (woe betide anyone showing up five minutes late wearing pants with martini glasses embroidered on them, as I learned the hard way). But some of the shtick, like the holy-card prizes and saint trivia, feels recycled. With more time to ripen, deeper dives into obscure Catholic lore, and perhaps more direct commentary on the state of the church--why should the nuns be put in charge?--Vicki Quade's production could still distinguish itself and match the appeal of the original. As is, it's an entertaining excuse to sing "Kumbaya" and get spanked with a ruler. Open run: Sat 5 PM. Royal George Theatre Center, 1641 N. Halsted, 312-988-9000. $25.