I love love this idea! I'm so mad at myself for not thinking of it first, actually. I saw the tree at IKEA (clever guys) a while back and instantly fell in love with the concept, but then I stood there forever pondering what on earth I could do with it. It goes without saying, though, that I would not go through the trouble of ordering felt ornaments online. I'd make them myself or I might even use paper for the ornaments with Christmas to-dos written on the back so I could easily change them out every year (or leave the tree as is because that's beautiful too).
These pyramids are so modern and funky! I kinda want to take the numbers off and just use them as neat tree ornaments. (It makes me sad to think they'll be opened for what's been hidden inside.)
This isn't originally an advent idea. It's just some paper trees hung with washi tape, but I thought they would make a really cute advent calendar. Just write a fun suggestion on the back of a tree and hang. I wouldn't even number them, I'd just turn them over at random. I also really like how they're stuck on a door. It enters the territory of modern wreath, too.
If you aren't into the traditional nativity scene, this'd make a nice edition to an empty table top. While I adore neon, I wish the colours were a little more festive (neon green and neon red? I dunno). There is a black and white version which would look extra cute if you found a tiny someone to add a little colouring pre-assembly, though.
You can purchase this advent calendar, but all you really need is a long piece of wood and a drill bit and you'll be in business. I can see this sitting in the middle of a table as part of a centerpiece.
Pro: You can fit a ton of fun stuff in a take-out container! Con: Take-out containers take up a ton of table space! Maybe you could use those cute little mini containers instead.
Finally, I thought it was really cute to make your calendar entirely out of cookies. (There's also a gingerbread version.) But, to be honest, in our house, I don't think they'd make it to 25!
There are a few more ideas on my Christmas Pinterest board and, if you missed it, don't forget to check out my advent calendar this year. I still think my origami balloons are the cutest!