Have you ever had an advent calendar? If so, this map may tickle your fancy, for while it has no chocolate, it does have presents, after a fashion!
Only 24 Days is an advent calendar made by Vilder50, built right into a Minecraft adventure map! It only has 24 days (which the name may have given away), and on each day, some new blocks are unlocked, which you can then use to build in the map's lobby, however you like! Of course, it would be simple if the blocks simply unlocked every day; however, the player must complete a challenge for each unlock! The challenges are fairly simple, but entertaining nonetheless.
The map can be played alone or with friends. Bear in mind, it was made for the most recent snapshot, so be sure you have that installed if you want to try it out!
You can download the map right here on Curseforge!