While you could go low-fi and just fill your fridge with 25 different bottles of beer, this would require an enormous amount of discipline to self-regulate and take away the fun of a different surprise beer every day. Instructables show you how to make a classy beer advent calendar using packing tubes filled with bottles of beer and covered with wrapping paper. I love the idea of punching through the paper every evening to extract that day's brew!
As awesome as this idea sounds, it does create one problem: unless you can buy 25 individual bottles of beer, you're going to end up with an extra five bottles of every beer and this becomes one very expensive advent calendar. I'm thinking it would be best to gather a bunch of beer-loving friends and go in on this project together.
I'd also get a kick out of doing this with a bunch of homebrewers. Can you imagine everyone brewing a batch of their favorite beer and then doing a big exchange at the beginning of December? I can think of no better way to toast the holidays than enjoying a different friend's homebrew every day of the month. (Note to self for next year on this one.)
→ Check out the full tutorial: Beer Advent Calendar on Instructables (via Laughing Squid)