There were SO many great advent calendar ideas on Pinterest, that it was hard to decide on just one! I ended up printing this cute little Christmas tree from here, and the blank calendar from here . I just wrote in an activity for each day. I have plenty of books from teaching, so we actually read one book and do one activity each day. It's nice to have the calendar in front of me, because if I don't have all of the supplies ready for one activity, I can look at another day and do that one.
One of the first activities we did was a "paint with water" velvet picture. I got this one at Wal-Mart for just under a dollar. (It's a great idea to go right after Christmas and stock up for next year, since these items go on clearance and they sell out quickly!)