Today, we have an advent calendar inside the advent calendar... from 1999:

From the deep within the BMH Online archives, I dug out the original BMH Online Advent Calendar that I created in 1999 (and probably hosted on Geocities, IIRC) - I don't recall where I got the idea from but the various gifs used behind each door I found around the web back then. With a few tweaks and improvements I have now made it function better than it ever did; now you can open each door yourself, whereas in the past I had to come in and do that each day (I couldn't figure out how to do that back then, but this time I employed ChatGPT's help).

Thank you to everyone who has been following along this year, and participating with their own.