Chicago's Museum of Broadcast Communications has made their archive much more accessible recently, though you still have to register..(It's free to do so..)
http://archives.museum.tv/registerArchive sign-up page..
Once you are in, you can search their database under various categories, one being quiz/panel/game..There are as of today 98 digital files available to view..be sure to check where it says "Digital File Available"..Among the shows available:
Down You Go (DuMont)
Beat The Clock
Concentration (1967)
Baby Game
It's Academic (Chicago) with NBC Peacock opening "Brought to you in Living Color by WMAQ-TV"-File is B&W though
It Takes Two
GE College Bowl (1959 and 60)
Jeopardy 6-27-74, 2-1972 (2000th ep.) and 1-3-75 Final of Fleming Version
Jeopardy Premiere 1984 (Trebek)
Just Men! 3-4-83
Masquerade Party (ABC) 1955
Pantomime Quiz (ABC) 1955
Music Bingo (NBC) 1958
Personality 1967
2ep. Queen For A Day ABC 1960
Public Prosecutor 1951-52 DuMont
Stump The Stars 1962 CBS
Supermarket Sweep both ABC 1966 and Lifetime 1991
This Is Your Life-several episodes from 1953-87
Tic Tac Dough NBC 1957
20 Questions DuMont 1952
Wheel of Fortune-1983 Syndicated Premiere
Just a representative sample..from early DuMont Shows all the way to Millionaire and Weakest Link..nice mix of game show history..