I overlooked this adventure for far too long. Now I rate it as one of my favourite 5e adventures so far.
Make your own megadungeon with Dungeon 23
It's 2023, and many people in the tabletop RPG space have decided to do 'Dungeon 23'. The principle is simple: a 365-room megadungeon, with one room for every day of the year. What a great idea!