I put little foam cut-out shapes into pockets for important events during the month - a cake for my hubbie's bday, a little sun for Solstice, and a gingerbread man for Xmas eve. We do celebrate both Solstice and Christmas at our house, though the Xmas part is really just a present grab for the kids. Solstice is the holiday of my heart.
My daughter looked at our main calendar, saw that I had drawn a candle on Solstice which is the 22nd this year. She then looked at our cloth calendar and saw the sun was peeking out from the 21st pocket from last year. When I came back into the room, she had moved the sun to 22nd. Clever girl! I'm glad to see they are teaching her something at her preschool. :)