July 31–Aug. 2. As many as 250 horses and riders enter this U.S. Equestrian Federation competition. Features dressage and stadium jumping, along with a cross-country phase that involves a mile-long gallop and jumping into water over barriers called “questions,” including logs, boulders, ditches, and banks. Refreshments. Pets must be on leash. 9 a.m.–5 p.m., Revel Run, 555 S. Dancer, Chelsea. Free. (734) 395–2633.