The 25th Annual Leatherstocking Gymnastics Meet is happening this Saturday and Sunday at the Utica Memorial Auditorium.    Sponsored by The Valley Gymnastics Booster Club, the event draws more then 600 athletes from across New York State.Level 3 to the highly skilled Level 10 will compete, ranging in ages from 6 to 18.   Event will be open to the public and runs Saturday from 8am to 8pm and Sunday from 9am to 3pm.