One from overseas this week. Radio 4's Brain of Britain has been going for 61 years and the format is as simple as can be. The contestant is asked a question and scores a point for a right answer. Further right answers score more points up to five, and a bonus point is awarded for a perfect run, at which point that turn is over so six points is the maximum score for a round. If at any time a wrong answer is given the other three contestants can light their lamp (and what a glorious effect this is for a radio quiz) and steal the point. The next player in line goes and whoever has the most points at the end of the thirty minutes wins and moves up to the semi-finals or grand championship.
Plus, every three years, the champion faces the two previous champions in a Tournament of Champions (Brain of Brains)...and every nine years, that year's Brain of Brains winner faces off against the two previous Brains of Brains in a Super ToC (Top Brain). I wonder if they have ever tried getting the three most recent Top Brains together.
I used to listen to this quite a bit when it was on BBC World Service (back in the days before streaming). The one Top Brain I've heard was in 1999, the year Kevin Ashman won. (I'd like to see Ashman take on Jennings and/or Rutter (although Rutter was lucky not to lose his Decades Tournament qualifier) for some sort of "world (or at least English-speaking world) championship.")
In fact, David Letterman was a fan of the show as well, and invited one of the champions on his show.