A few I can think of...

Philip Cousin told me when he was on Wheel, they told him and the others not to look at the wheel upon spinning it. They didn't want anyone trying to finesse the wheel spin to land exactly where they wanted it, and if they suspected you looked at the wheel, they'd make you re-spin.

Randy Amasia told me and a group of game show fans that on Whew!, they were discouraged from saying "I don't know" as a response to a blooper if you didn't know... either make a wild guess or say nothing, not that it was a rule, just something they discouraged.

Not really a rule, but Frank Wayne later had an aversion to potential contestants saying "I don't believe it!" on TPIR. He would discourage the producers from picking contestants that uttered that phrase in line.

A random episode. Especially if it's a show that I know, I would get bored with hearing the rules explained for the debut, and on the other end, don't need to see gameplay cut for a lengthy, sometimes emotional, goodbye.

I think I'd go for finales. Most of the last shows I've seen appear to be like random episodes with the usual game play with just a brief goodbye at the end instead of a big deal like What's My Line.

A random episode. Especially if it's a show that I know, I would get bored with hearing the rules explained for the debut, and on the other end, don't need to see gameplay cut for a lengthy, sometimes emotional, goodbye.

Random. I always get a weird sense of bittersweetness watching finales, and the premiere is usually a little awkward.

Here's a question: If you could somehow get a copy of every network game show that has aired since the late 40s, would you rather have the debut or the finale or just a random episode?