To make these Jack O'Lanterns I have the kids cut out the pumpkin shape first, they could draw it or you could give them a printed out version.
After the shape has been cut out I have them hold out their hands and I put one drop of red and one drop of yellow in each hand. I then tell the kids to put their hands together and mix around the paint and to their amazement it turns orange! Just like magic! I then have them finger paint the pumpkin, spreading the color all over the pumpkin. It's a great way to start a discussion about creating secondary colors.
Next we cut out shapes for the face and Voila, a jack o' lantern is done!
For more fun Halloween ideas check out the links below: (click on the photos)