The Gallery Players' 40th season opens with a double-bill of one-act plays by Christopher Durang: The Actor's Nightmare and Sister Mary Ignatius Explains It All for You. In 1989, this hilarious double-bill of one-act plays was the inaugural production in the 99-seat Park Slope venue that remains The Gallery Players' home to this day. The Actor's Nightmare is a hilarious spoof detailing the plight of a stranger who is suddenly pushed on stage to replace an ailing actor. In Sister Mary Ignatius Explains It All for You, the titular Sister, a teaching nun who is much concerned with sin in all of its various forms, delivers a cautionary lecture to her charges. But when several of her former students turn up the picture darkens, along with Sister Mary's indignation.