Harry S. Murphy was a contestant on April 10, 1991. He came in second, after the other challenger had a negative score at the end of the main game. The champ outbid him for the triple question, though, sealing his fate.
The onstage Judge was a writer for the original Squares, and won an Emmy for his work there.
The Judge (after both Clark and the Studio Audience start to loudly groan at the puns): I proudly stand behind my writers...very far behind them.
Keep Circulating the Tapes: It hasn't been seen since its original run, but prominently displaying the airdate in each episode makes collecting pretty easy.
Talking to Himself: A very odd example. The Home Participation Sweepstakes featured questions that a recorded Dick Clark asks when the viewer calls the 900 number given on the show. During one promo for the contest, Clark admitted to calling the number himself to see what it was like, concluding with "It was a very odd experience to talk to myself."
Throw It In: Given the format of the game, unless all three contestants pick one question apiece or all three pick the same question and go on to sweep the board, one question per category will go unasked. Generally, Dick will save the question so it can be reused (at least one episode had a category called "Challenger Leftovers"), but every once in a while he'd ask the Judge for permission to ask the leftover question just for fun if he thought it was particularly clever.