Rules of the LawnA standard leather medicine ball. Taking walks or rides early in the morning is a lonesome business, and the inevitable secret service guard when the president leaves the White House grounds is not enlivening company." There was science behind Hoover-ball—it was White House physician Admiral Boone who actually codified the rules. The game was contested between two teams of between two and four players, using a six-pound medicine ball and an eight-foot net. Games of Hoover-ball began at 7 a.m. on the south lawn of the White House.