Through four seasons of Impractical Jokers, the guys have never shied away from a challenge. Whether they're clipping balloons to strangers in a supermarket or pitching a humiliating autobiography to a focus group, Joe, Sal, Murr and Q do everything in their power to make each other squirm as much as humanly possible. In this special episode, the Jokers look back on the series' very best challenges and dish out behind-the-scenes secrets that have never been shared before.