Huh. Interesting question.
* In general, the finale of any since-destroyed game show that acknowledged it was the end (such as Eye Guess, where they apparently took out the "STOP!" card for the last bonus game)
* Concentration: 1958 premiere, Downs' last day, Clayton's first (both in January and September '69), McMahon's first and last shows, Ed's only anniversary show (where he and Johnny Carson played while Clayton hosted), first color episode, Teri Coffin's 20th win from 1973
* The Hollywood Squares: 1966 pilot, premiere, first and last Vegas shows
* Jeopardy!: Merv's original What's The Question? runthrough, 1964 premiere, the rest of the September 7, 1966 show
* Password: 1961 premiere, 1971 premiere, last pre-All-Stars show, first All-Stars show, first "big-money Lightning Round" show, anything from when Monty Hall or Betty White hosted
* The Price Is Right: 1956 pilot, series premiere, last NBC daytime show, first ABC show (both versions), 1965 finale, Dennis James' first and last shows
* Pyramid: last $10,000 episode, first $20,000 episode
* Second Chance: Pilots #1-2 and premiere
* Snap Judgment: last episode of the first format, first day of the Password format
* Three On A Match: last day of prize-matching/first day of picture-matching, any episode from the last week or two (where I'm sure Bill was buzzsawing through the material even more than he was in February)
* Wheel of Fortune: last episode with the Buy A Vowel wedge, the episode immediately following it, any hour-long episode, any episode from 1977 (the only year that doesn't have any audiovisual examples), first and last Star Bonus shows, the very first use of the five-and-a-vowel Bonus Round, last day of Thicke's cues/first day of Merv's, anything from the Ohio State Fair week in August 1983 (the first nighttime week for some affiliates in that state)