Actor Jack Palance was once caught napping in his square during a taping; he had to be awakened by fellow panelist Michael Landon when a contestant called on him.
Retired, reclusive actress Greta Garbo was such a big fan of the show she actually wrote a fan letter to Paul Lynde in care of the show's taping location at NBC Burbank.
Host Peter Marshall had said that most of the episodes were destroyed by NBC. But a Cable TV station found 3,500 episodes (while looking for the TV series Dark Shadows (1966)) and were sent to Game Show Network. Episodes began airing on April 15th, 2002.
Ernest Borgnine was the original center square, when the show premiered on NBC on Monday, October 17, 1966. Paul Lynde appeared the second week but didn't appear in his permanent center square position until the fall of 1968.
Celebrities were not required to give the right answers for any questions. They were briefed before each show to help them with possible bluff answers, but were hearing the actual questions for the first time when each show was taped. Certain celebrities were often asked questions pertaining to specific categories. For example, Paul Lynde frequently got loaded questions just so he could come up with an initial funny response.