The Suspicious Clowns often tip sacred cows to humorous effect. But this show, written by the sketch comedy ensemble's members Robert Felker and Vincent Truman and directed by Felker, pushes too hard. Puerile sexual humor and jokes about shootings, rape, and pedophilia are used to skewer broad, often undeserving targets: the Germans are all Nazis, the Irish eat a lot of potatoes, Italians are dumb and violent, the Scots wear kilts and discuss their testicles. The rambling sketches go on far too long and are too often centered around Truman, who can be a good performer but here seems only to be trying out different accents. Though the show has imagination--a sketch about being locked out of a car throws in a badger and plastic explosives--too often the juvenile mentality undercuts the scene. Through 5/28: Sat 10:57 PM. Trap Door Theatre, 1655 W. Cortland, 773-384-0494. $12.