If friends call you this weekend and offer you their extra ticket to Of Thee I Sing, which has been sold out for weeks, say, "Yes!" The only disappointing thing about this revival of the 1931 Gershwins' musical comedy at Bard Summerscape is the brevity of its run. Director Will Pomerantz has given the Pulitzer Prize winning show a taut, thrilling production that is both historical and relevant, and the casting is remarkable because the faces look like those you recall from the great Marx Brothers movies. It's a screwball musical in the tradition of Animal Crackers (and Of Thee I Sing's book was in fact written by George S. Kaufman and Morrie Ryskind, who wrote screenplays for the Marx Brothers.) The deconstructed plywood sets give the play an avant-garde look, but otherwise the choreography and costumes transport you to the Great White Way of the Depression era. As if to emphasize the historicism, the actors do not wear body mikes and their voices, while not loud, are clear and fresh as is the timeless Gerswhin music under the confident baton of James Bagwell. And, of course, the story of a presidential campaign focused on style rather than substance could not be more timely. Bravo to Bard for bringing Of Thee I Sing to us (and shame on Bard for not anticipating its appeal and booking a longer run.)