Hoover-ball was invented, developed and perfected by White House physician Admiral Joel T. Boone to keep Hoover physically fit. It is a combination of tennis, volleyball and medicine ball. Teams of up to five people play on a court 66 feet by 30 feet with an 8 foot volleyball net. A 4 or 6 pound medicine ball is used and scoring is exactly like tennis. – History of Hoover-Ball, Hoover Association
Cabinet playing in South Lawn of White House – 1933
References:
Hoover Association – http://www.hooverassociation.org/newsevents/hooverball/hooverball_rules.php
Main Photo – http://crossfitmidtown.com/2012/06/29/franday-06-29-12-athlete-profile-uran-piedra/
First Photo – http://www.hoover.archives.gov/education/hooverball.html
Second Photo – http://portaldoprofessor.mec.gov.br/fichaTecnicaAula.html?aula=26650