The open gym. Gymnastics. parents and their children share in a special time together while the child participates in tumbling, obstacle courses, balance beam and bars.Children are encouraged to explore their abilities, use their imaginative skills, enhance listening capabilities, socialize in a group and develop gross motor skills. Theme weeks, music, ribbons, balls and other fun equipment are used to make it a fun and developmental experience. Ages: 1.5 to 12 years old.