One of the fun little traditions in our family is to have a Christmas countdown chain. It's a fun, easy, and inexpensive project you can do with your kids. Even when we didn't have our daughter and granddaughter living with us I would do a countdown chain, just because. The idea is to remove a link every day in December until you have one left. Then it means it's Christmas!
Basically all you do is cut 25 strips of paper and tape or staple together to make a chain. The thinner you cut the strips, the longer the chain will be. This year I cut the strips a little thicker so it doesn't hang so low.
You can make it out of different colors of construction paper like I did this year. Or you could have one color for each week with a separate color for Sundays. Or all one color with Christmas Day a different color. I try to make Christmas Day something special, like all sparkles. You can either number the days or not. I like to number them to make it easier to remember if a link has been removed. I didn't pay attention to if the numbers were right side up when I stapled them together because I did it right before I went to bed. It doesn't really matter unless you are a profectionist or you have OCD or whatever.