Well, here's a bump for a weird, unconfirmed one.
Cubby O'Brien was a child star, one of the original Mouseketeers and a drummer on
Lawrence Welk for a couple of years. After his brief stardom, he continued to work as a drummer (most notably for The Carpenters) but only turned up in newspapers as part of "Where Are They Now?" style features, or stories about the occasional
Mickey Mouse Club reunions.
According to his Wikipedia page, with all the caveats that implies, he won $5,000 on
The Big Showdown.
I kinda think it's true. There are few attributions on the page, but like so many quasi-celebrity pages, it feels like it's been written by a family member, or maybe the subject himself. An appearance on an obscure game show seems a strangely unusual and specific thing to just make up. Finally, if he went on the show as Carl O'Brien instead of using his ursine nickname, he probably would avoid all the "Hey, weren't you...?" drama.
Thanks to our own Mike Burger (mmb5) for noticing the reference in the first place.
https://en.wikipedia.org/wiki/Cubby_O%27Brien