And you thought your day at work was bad ...
According to Stephen Sondheim (who was a production assistant for the original Broadway production) ... Allegro may have suffered the most disastrous opening night in theatre history. In addition to a falling flat, during a dance number in Act One, one of the actors caught his tap shoe in a track on the stage, tearing every ligament in his leg, and had to be carried - screaming - from the stage. In Act Two, Lisa Kirk, who was making her professional stage debut, caught a heel in another track and fell headlong into the orchestra.