I started a sudden death series in which your goal is to find all countries that border a country that borders a given country, while not bordering said country itself.
It is quite tricky but a lot of fun (in my opinion)! Currently there are 4 quizzes live - Russia, Turkey, Niger, and Colombia, with more to come if you like it!
Appreciate all feedback, and if you have any ideas for a better / shorter series name, please let me know!