This 6½ minute clip of "The Newlywed Game" from 1966 was found on another website which, unfortunately, no longer exists. Bob Eubanks is the host but almost everything else in the clip is different. Also, this episode survives on a black-and-white kinescope instead of videotape. Color VT came later. And finally, as far as I know, this episode may be in the public domain.
Here's the closing for a 1989 installment of "The MacNeil/Lehrer Newshour".
I don't know the exact date but it's probably between March 27 and April 5.
This is all I have of a 1998-ish episode of "The Price is Right". If anyone has the date for which these three people participated in the Showcase Showdown, let me know.