Give your toddler red and yellow paint and allow him to mix them on a palette or simply by combining the paints on a piece of paper. He will soon notice that when the colors are mixed, they turn into orange. Ask him to try mixing in more yellow or more red to see what happens to the orange color. See how many things he can think of to paint that are orange.
Have your toddler paint a paper bag orange and let dry. Then, using black paint or a black marker, have him draw a jack-a'-lantern face on one side of the paper bag. Let that dry fully. Let your toddler crumple up sheets of newspaper into balls and stuff them into the paper bag until it is round and looks like a pumpkin. Tie off the top of the bag with string or an elastic. If you like, have him twist a long, thick piece of construction paper to look like a stem and glue it to the top of the bag. Let young toddlers color the bag and draw the face with crayons instead of paint, or simply color in a jack-a'-lantern face on a piece of paper.
Lay out all sorts of orange materials, such as scraps of paper, yarn, ribbon, buttons or anything else you have that a toddler would find interesting. Ask your toddler to create a collage by gluing all the orange items onto a piece of paper. Or have him glue all the pieces to create an orange picture, such as a pumpkin, orange or orange leaves on trees in the fall.
Cut up oranges, carrots, small squash or mini pumpkins and have your toddler dip the fruits and vegetables into orange paint and then make prints with the paint. Add other items if you can, such as orange flowers or leaves, or even orange sponges cut into interesting shapes to appeal to a young child.