Get the little gourd pumpkins and have them paint them...or put stickers on them.
Stuff a scarecrow..
Instead of a gingerbread house, make a Halloween house.
Use the little mini milk cartons or make your own base... Use red icing (or chocolate/black), and use graham crackers..
They can use icing as the "glue" and use Halloween candy as the decorations...
Ghost lollipops..
Antoher craft, Halloween votives..
Take baby food jars, and overlap orange tissue paper on them (using clear glue) BE CAREFUL NOT TO GET ANY ON THE INSIDE!
Then you take a small amount of black tissue paper, and do small triangles (eyes) and teeth.. Glue those on top of the orange...
Use Halloween shaped fun foam to make magnets...or picture frames.