Begin your Friday the 13th date in Evanston at Northwestern University's Block Museum of Art (40 Arts Circle Drive, Evanston, 847-491-4000; free), where "Polaroids: Mapplethorpe" is showing in the Alsdorf Gallery. The exhibit features more than 90 casual snapshots by controversial American photographer Robert Mapplethorpe that should get your juices flowing. When the museum closes at 5 p.m., head south and kill a couple of hours at the Kit Kat Lounge & Supper Club (3700 N. Halsted St., 773-525-1111). Tribune restaurant critic Phil Vettel says the place augments its surprisingly respectable chow with playful cocktails and regular performances by the "Divas," Kit Kat's elaborately costumed female impersonators. After dessert, head to the Abbey Pub (3420 W. Grace St., 773-478-4408; $12 advance, $15 at the door) for the 9 p.m. Broken Hearts Burlesque Ball, hosted by Belmont Burlesque Revue. Round midnight, head to the Music Box Theatre (3733 N Southport Ave., 773-871-6604; $12 presale, $20 "sweetheart deal" presale pair, $14 at the door) where former Miss Exotic World Michelle L'Amour and the Chicago Starlets will perform "Belles and Whistles: A Valentine Burlesque Revue."