Still, when I think "Holy Grail", I think of a series for which absolutely no video is known to exist, especially a successful series. And I think the general consensus of the board tends to be that the 70s Sale of the Century is the biggest current Grail.
UCLA holds nine episodes of the original
Sale, albeit "noncirculating", and I think that was your point. If we're talking about "successful game with no video known to exist", I think
Snap Judgment would be a very high candidate.
I'd also like to see the special daytime Community Chest episode of What's My Line? that was discovered some years ago.
Saywha? Never heard of this one. Could someone explain this, please?
If we can go international, I'd love to see how Reg Grundy tackled the original
Price Is Right and
Second Chance for Australia, as well as a full episode of the 1970s
Price that shows up in retrospectives from time to time. I'd also love to see an episode of the 1950s
Wheel of Fortune that aired in America (different game to Merv's, albeit with some general similarities from what I could dig up...and apparently Mike Wallace hosted it later on).