I use these blank calendars as a monthly center. Students are to fill in the boxes according to the correct date. They then glue the completed calendar to a 18x12 piece of construction paper. On the top portion of the construction paper students complete an art project that corresponds with the month. I make the art portion of the calendar something different each month. I have them use many different forms of media - tissue paper, paint, watercolors, mosaic construction paper pieces, stamps, stickers, etc.
You can use them however you want!