About this time of year I give a link to this site from which you can download a calendar to cut out, fold and glue. It should keep the kids occupied for an hour or so and makes a nice present for grandma to hang on the tree.
If you make a mistake, throw it away and print another.
Tip: cut the tabs down to about half as long and leave the side with no tabs (November) until last. Score all the folds before bending.
http://folk.uib.no/nmioa/kalender/Keith