Movie Gag

During the filming of the sleeping bag scene in Prisoner of Azkaban, director Alfonso Cuarón, Michael Gambon, and Alan Rickman played a practical joke on Daniel Radcliffe (who had requested to have his sleeping bag next to a girl whom he liked at the time) by hiding a remote-control-operated Whoopee Cushion in his sleeping bag. According to Cuarón, Daniel tried really hard to stay in character while everyone else was laughing.