On Where in the World is Carmen Sandiego?, to fill time in case a show ended early, The Chief would call an audience member into her office to ask them a geography question. If they give a correct answer, The Chief gives the member a Carmen t-shirt, while an incorrect answer resulted in winning a world atlas.
On some Classic Concentration episodes, there was an audience game that was played like the car round, but for a cash prize of up to $500. There were prizes of $5, $10, $15, $20, $25, $50, $75, and $100.
Also, probably my favorite audience game, Face the Devil from the syndicated run of The Joker's Wild in the '70's and '80's; three audience members would be called and each would have one spin of the reels. In the first round, amounts were as low as $10 and high as $50, IIRC. The highest scorer would play against the devil like the on-stage contestants would; try to accumulate $1,000 or more without seeing the devil, and they'd win the money and a prize.