The folks at Guinness World Records just announced that the University of Notre Dame set a world-record on March 2, 2012 in the Purcell Pavilion in a game called "knock-out basketball."
433 participants -- smashed the previous world record of 379!
Here's a link to how you play this game -- along with a link to the World Record:
LINK: KNOCKOUT BASKETBALL RULES
LINK: GUINNESS WORLD RECORD!
