Amy Poehler imagined how her character on “Parks and Recreation,” Leslie Knope, might react if she ever moved from Pawnee, Ind., to New York. At the opening of the Upright Citizens Brigade’s new theater, UCBeast, Poehler said Friday night, “She would be overwhelmed. She’d be impressed by the number of languages people speak on the subway, but irritated by the price of the lobster rolls.” Also at the comedy troupe’s new digs were comedians Horatio Sanz and David Cross.