I'd made mention of this in the Brickset Builders Guild section, but figured it might be worth starting a new discussion since I'll be adding to it.
This year I have created a LEGO Harry Potter advent calendar for my wife, who is at the tail end of a master's degree and hasn't been able to do one of the retail calendars alongside our daughter (7) over the past few years. She was thrilled with the surprise reveal on Saturday and is enjoying it so far! In the spirit of official LEGO advent calendars, it's a mix of builds in various scales with a selection of minifigs scattered through the days.
On the production side, I've repurposed and fully rewrapped last year's Star Wars calendar. (Graphics on the box borrowed from a freely-available Wizarding World coloring book PDF.) The builds throughout are mostly original, with inspiration drawn from official LEGO sets and other MOCs around the web. I'll note relevant items as we go.
Here's the box. The production of the door panels was a little rough as I forgot the LEGO calendars have a staggered layout. Perhaps next year I'll build the whole thing from scratch, but for the first go-round this will suffice.
Hope you enjoy this, and maybe with some luck we'll see an official version of this next year! I'd absolutely be in line for that.