We have this big advent calendar that my mom made for us after my son was born. It hangs on the wall in our living room and has little candies in it. I was absent mindedly staring at it when it occurred to me that most of the pockets would be the right size to hold Famicom carts. So I took the candies out and put my son's Famicom carts in.
This was just a test run and I have no plans on ever doing anything like this, but I thought this would be a pretty cool thing for a retro gamer to do. Especially if you are like a retro gaming couple who live together without kids this'd be an awesome way to do advent calendars - playing a game each day throughout December.
I'm not in that category of person, so this advent calendar was retro-gamified for demonstration purposes only, and currently has reverted to holding just candy. But I thought I'd put the idea out there in case it hasn't already been floating out on the internet since like 2007 or something and I just didn't notice!