What about the '60s / '70s Newlywed Game? Did they ever do a Bring Back Teh Losers week? I think they did on New Newlywed, but I'm talking the original white-picket-fence version.
Didn't the ABC version have episodes with expectant mothers? Does that count?
With Gambit, the only thing I can think of would be special prizes in the bonus round. The Vegas version had a singles week, but I think the CBS version qualifies.
How about Celebrity Sweepstakes?
Gambit had an annual event (early Februarys, I think) where the first couple to get a 2-card 21 in the bonus round won $10,000 (at first, it was $200/week for a year). I vaguely remember that, the third year they did this, it lasted into the Washington's Birthday holiday, and Wink mentioned that in the first two years, it had been won in the first week both times.
Celebrity Sweepstakes had a Christmas Day special one year with Pat Boone playing against Flip Wilson. No, I am not confusing this with the other show (Wheel?) where they played each other, and, IIRC, for the same charities - the American Cancer Society (Flip) and the Boy Scouts of America (Pat). It was the first time they had the spot lights inside of the numbers, presumably to make it easier for people with black and white TVs to see what numbers were lit up when they revealed who had the correct answer to a question. I even remember the final question - "Who sang, 'Christmas, Christmas time is here; time for toys and time for cheer'?" (answer: Alvin and the Chipmunks) - and also that it replaced another All or Nothing question that had been scratched, although I have a feeling it was scratched because both contestants chose somebody who got it wrong.
There was also the "Shamrock Sweepstakes" involving six winners from NBC's six game shows at the time (CS, Wheel, High Rollers, and I think Hollywood Squares, Jackpot, and Jeopardy), and a week of celebrities (mainly from NBC soaps, although Chuck Woolery and Susan Stafford played on the last day) playing for home viewers with a grand prize of $75,000.