City, county, and state parks cover 26,000 acres of the Pittsburgh region, so there's a park to fit almost any outdoor pursuit. Besides trails for hiking, biking, rollerblading, and riding, many parks have facilities for cross-country skiing, tennis, ice skating, sled riding, swimming, volleyball, and picnics. Golfers can tee off at one of 146 courses, and the Oakmont County Club is home to the annual Mario Lemieux Celebrity Golf Invitational and will host its eighth U.S. Open in 2007.