In Sweden, there’s a long tradition of TV and radio advent calendars: shows, often Christmas-themed, that are exactly 24 episodes long. Each of the 24 days in December leading up to Christmas, a new episode drops. Whether this year’s advent calendar shows are better or worse than last year’s is always a hotly debated topic. But, obviously, the best calendar shows were the ones airing when I grew up.

That’s why I was particularly pleased when I won a mint-condition, unopened advent calendar for the 1994 radio show Hertig Hans Slott at an online …