A very simple and fun exercise to train change ringing students to listen keenly. Lots are drawn for which ringer will be the joker. Only the joker knows; the other ringers are not told. The ringers pull off in rounds, and once the rounds have settled, the instructor calls: "Go Joker". The ringer who drew the joker card then deliberately rings badly, clipping or leaving a big space. After a minute or two, the instructor calls "stand", and the students discuss who they think had the joker card. They have to listen carefully during the ringing to hear who is ringing off beat, and no one wants to be falsely accused of being the joker.