The Elephant in the Room

Carol Burnett had just lectured the cast of The Carol Burnett Show about going off script and making the rest of the cast break character. That's why Tim Conway went way off script about an elephant that had the cast and the audience in stitches. Even Tim Conway! How this happened is explained here. Of course, they had to do the scene again and again. Vicky Lawrence has more. (via Metafilter)