The works on this program are "American" in the sense that they're based on American folk dances. George Balanchine's Square Dance is annoyingly faux-naif--a caller exhorts ballerinas to "Promenade, pretty girl!"--but intriguingly adds ballet moves and chamber music to a square-dance template. The corps was sharp, though the lead couple made every maneuver look effortful. Antony Tudor's Dark Elegies, making its Joffrey premiere, creates circle dances and Virginia reels using angular moves a la Martha Graham. The piece seemed lugubrious except in Erica Lynette Edwards's solo, danced with a restraint that magnified its power. The program's highlight is Jerome Robbins's N.Y. Export: Opus Jazz!, which follows folk patterns but with splayed hands and strutting feet. Dancers coupling in vivid sweatshirts and Keds erase any doubt that "jazz" means "sex." Again the ensemble outshone the soloists, but the work's so buoyant it hardly mattered. Through 3/20: Fri 7:30 PM, Sat 2 and 7:30 PM, Sun 2 PM. Auditorium Theatre, 50 E. Congress, 312-902-1500 or 312-739-0120, ext. 20, for groups of ten or more. $15-$98.