Christopher Durang’s 1976 farce was conceived as a satiric bicentennial response to late-60s angst–an alternately mocking and morbid portrait of an American family wrestling with Vietnam and its aftermath. But Chemically Imbalanced Comedy’s engagingly scruffy production reveals Durang’s dark comedy to be a timely satire of a nation muddling through a war abroad and political polarization at home. Durang mocks pro- and antiwar cant with equal fervor in his tale of an ultradysfunctional family: bossy but loving mom Ozzie Ann, ineffectual dad Harry, rebellious teen son Et, and older brother David, a blind Vietnam vet turned protester. The actors bring insight, energy, and integrity to the material. And Durang’s take-no-prisoners approach gives the play a contemporary edge. Through 10/8: Thu-Fri 8 PM, Sun 5 PM, Cornservatory, 4210 N. Lincoln, 773-865-7731, $15.