TIFF AND MOM AND THE OUR LADY OF BERWYN CARDIOPLEXOFLEX FUND-RAISER FRESHMAN FORMAL, Corn Productions, at Sweet Corn Playhouse. Rife with terrible running jokes, outlandish names (Dr. VonSchtuckinapetriedish), fatty wisecracks, and the groaner gags that killed vaudeville, the Tiff and Mom series keeps merrily mutating, secure in its cult niche as the silliest show on Clark Street. In this lowbrow, blue-collar spy thriller, Robert Bouwman (adipostic teenage Tiff) and Todd Schaner (her horny, sozzled mom) put the belles of Berwyn through various crackbrained exploits. While organizing a fund-raiser to fight “cardioplexoflex,” a flesh-eating virus that originated in Cicero, Mom and her spawn contend with stupid spies who hope to win fame by filching the coveted cure.

The plot’s a paltry pretext for the taste-defying 15-member cast to rampage through complications ranging from the hilarious to the tedious, spoofing reflex sex, high school hysterics, and suburban stupidities. It culminates with a benefit at the “Berwynadrome,” where Tiff and Mom work out their mother-daughter issues and wail their trademark song. Louder than life and wearing wigs that might qualify as EPA Superfund sites, Schaner and Bouwman turn their dysfunctional duo into irrepressible cutups. The spies are the last word in xenophobia, and Maurice Doggan and John E. Blackmon are sidesplitting as a funky, chunky mother and daughter. Their dance routine may not bring down the house, but it sure shakes the stage. –Lawrence Bommer