Take sandpaper and cut into squares then give the kids a cinnamon stick to rub onto the sandpaper (so they smell). Trace a gingerbread man shape over the sandpaper (use either a cookie cutter or you beforehand trace onto cardboard for all the kids) and cut out. Let them outline and decorate with puff paints and punch a hole in the top. It looks pretty easy. I was thinking of using for my daughter's Kindergarten class.
Some other things we've done:
Someone make or buy sugar cookies in shapes and let the kids decorate with icing!!
Make snowmen: Put 2 or 3 marshmallows on a toothpick and use pretzel sticks for arms and dab a bit of icing and add mini morsels for eyes and mouth. They're cute.
How about making ornaments of some sort? You can do paper and glitter ones that are easy to handle. I use cookie cutters to make my designs, because I can't even draw a stick man! The kids use puffy paint pens, glitter, glue, etc. Then there's the cinnamon ornaments, but that takes a few days. You could make clay ornaments at home and have them to paint them. There is also the paper plate wreath. My kids liked doing that at school. So what is your budget?