I’ve finally added the challenges feature to the site! For now, only quizzes where you don’t choose an option at the beginning of the quiz (i.e. ‘choose year’ or ‘choose number’ quizzes are not implemented yet) now will have an ‘Issue Challenge’ button after the quiz is complete. There is also a ‘My Challenges’ menu option at top which will take you to your challenges page where you can see stats and set challenge preferences. Let me know via the contact form if there are any issues.