I had toyed with the idea of doing a Jesse Tree this year, but I think we'll wait a couple of years until Sweet Pea is older.
This year I think the punchable advent calendar will be perfect for my preschoolers, but Superman will enjoy it too.
I was able to round up most of the supplies for this project around the house. I did have to run out to the store for a couple of things though.
If you decide to do this but can't put it together by tomorrow, you could just shorten your Christmas countdown and begin whenever it's convenient for you. :)
Here is another advent idea that we did last year.
Finally, here is a wealth of advent resources and ideas archived at Teaching Mom. It would take years to use all of these ideas. (Apparently this page was created in 2007, and some of the links are broken. Aside from that this is a treasure trove of information and ideas.)
Let the countdown begin!