So I made this little calendar for our house. It doesn't cost much - just a bit of ribbon, wooden pegs and pretty scrapbooking card and a sharpie (I love sharpies).
I love that red and white candy striped ribbon/twine now available at sewing shops. I use it for so much - it's great for wrapping around gifts too.
This advent calendar spells out "We wish you a Merry Christmas." That's 24 letters, in case you didn't notice. On one side write the letters, on the other the number. So each day we turn one card over and there's a new letter. Good spelling practice too, if you homeschool - except they guessed it on day 3. Oh well!