Knock Knock, Who's There? Wipeout

"Want to know the Wipeout recipe? Take 24 contestants, 10,000 gallons of mud, four Moving Big Balls and shake briskly. Serves: Everyone!," said host John Henson. And don't miss the Door Knock and Pendulum Shape Shifter that are showcased on this week's episode of "Wipeout," featuring the world's largest obstacle course.