I thought that if a player hit zero on $ale of the Century, they were out of the game.
That was the rule on the old Jack Kelly / Joe Garagiola version - at least, before it switched to couples. (On the weekly syndicated couples show, if a couple got down to zero, both couples got an extra $20.)
Blame it on the dozens of Milton Bradley editions, but I thought the Narz version of Concentration had FORFEIT squares and gag gifts and the Trebek version was the first incarnation that did away with them.
I knew it didn't have gag gifts, but did it really not have any Forfeit squares?
I have had quite a few false memories - the earliest one I can think of: I thought Dick Clark hosted the original You Don't Say!.
Some others:
I thought the original The Joker's Wild had a five-game limit, instead of the Joker Jackpot. (That's what happens when you only get to see the first week before school starts - and on a 5" black and white screen without a cable hookup, at that.) I also thought that, after the car was won in the first week, it was replaced by a boat (instead of a trip to Mexico).
Apparently, that "52-day Mediterranean cruise" I remember being on a lot of shows (Name That Tune, Pro-Fan, and some Dealer's Choice) was actually a South American cruise.
I thought the first episode of TPIR didn't have either Bonus Game, but some variation on Clock Game where you get seven guesses to guess the price of a car, plus Grocery Game and Double Prices.
I also thought "Moneymaze" was one word throughout the series. Oh, wait - pretty much everybody else had the false memory that it was two words "except in the pilot."