Reminiscent of Oklahoma!, Rodgers and Hammerstein's 1945 follow-up celebrates love between man and wife, boy and girl, farmer and pig. Written for film, then remade for stage and screen over the next 50 years, it picked up an assortment of "trunk songs"--material from other shows--along the way. These jell to produce a tuneful, memorable score--as Sunday's audience demonstrated, humming vigorously, if largely off-key, to "It's a Grand Night for Singing." The superb cast's exuberance keeps the Iowa corn from turning to mush, and Thomas M. Ryan's clever set evokes the fair's magic with little more than bold signs and twinkling lights. This is a show sure to induce hankerings for corn dogs and elaborate butter sculptures. Through 7/2: Wed 1 and 8 PM, Thu-Fri 8 PM, Sat 5 and 8:30 PM, Sun 1 and 5 PM, Marriott Theatre in Lincolnshire, Rte. 21 (Milwaukee Ave.), Lincolnshire, 847-634-0200, $42-$45.