baby sock advent calendar - totally useful for all the single socks from the kidlets. Fill with small candies or chocolates, dollar store toys (but try to avoid junky ones that will just create clutter), hair ribbons/clips, etc. WAY more realistic I'll do this one than the pocket sewing ones I've seen.
Christmas advent calendar--I had been saving toilet paper rolls for awhile now--perfect for this idea. My plan is that each holder will have part of the Christmas story from Luke 2 in it so on Christmas eve we read about the birth of Jesus and then we can watch the Nativity movie.