I'll piggyback on this. I recently gave my mom the first season of Fantasy Island. There are no small number of guest stars who were celebs on game shows. Of particular note, though, was a story from either the first or second episode with George Maharis and Adrienne Barbeau, who faced each other on Cullen's $25,000 Pyramid. That was the only instance of two people who weren't otherwise associated doing both. (Steve Allen and Jayne Meadows did an episode of FI and faced each other on $10KP and P+, but they were married.) One other pair of celebs, Maharis and Elaine Joyce, faced each other on Pyramid and were in the same ep of FI but in separate story lines.