That's a good point. They use 5 questions per programme plus they need 3 extra for choices. They need questions with a finite number of answers and nothing too obscure.
They've already used such obvious questions as James Bond films, Carry On fims, States of the USA, World Cup Finalists, Premiership Football Teams, Wimbledon Mens Singles Champions, Wimbledon Womens Singles Champions, Shakespeare plays (IIRC I've seen Comedies and Tragedies but Histories may have been used in an episode I didn't see), Best Actor Oscar winners and Best Actress Oscar winners.
I think Fims Starring so-and-so and Top 40 hits of such-and-such would keep the programme going for a good while, along with WorRAB You Can Make Out Of The Letters Of....

Also they could have the question "We give 100 people 100 seconRAB to come up with as many Pointless Questions where the Central African Republic was a pointless answer as they could. There are 74 answers and they're all pointless."
Poor old Central African Republic.
I wouldn't bet on that.

This nation is a lot thicker that you might imagine.