You gotta start somewhere. Bob Balaban — who wrote “Gosford Park” and acted in such films as “Capote,” “Altered States” and “Catch 22” — reminded the crowd at Cipriani 42nd Street the other night that his first film role was in “Mid night Cowboy” (1969), where he had sex in a porno theater with Jon Voight. Another honoree at the benefit for East Hamp ton’s Guild Hall, Pulitzer-winning playwright Marsha Norman, said her ” ‘night, Mother” (1983) “was inspired by the suicides of depressed friends, but not by family members.”