Taking a walk gets children moving, so take a hike in the area around your school. Let the birthday child be the line leader on your walk. As long as you're walking on flat ground with plenty of room, encourage him to walk in silly ways. The rest of the children must follow the leader and walk like him. Once you've walked for a bit and observed the fall leaves, spread out a blanket and have a picnic-style birthday party.
Having children make birthday cards for one another helps them with their writing practice. Incorporate fall into the cards by having children make leaf rubbings. Collect a variety of fall leaves and spread them on a table, vein-side up. Give each child a piece of white paper. Remove the peels from small pieces of crayon. Have children place their papers on top of the leaves, then rub the side of the crayons over the leaves to create the impression of leaves on the paper. Once they're done, have children turn their papers into cards for the birthday child.
Enjoy birthday treats inspired by fall holidays. If Halloween is approaching, give children cupcakes decorated like pumpkins. If it's closer to Thanksgiving, serve cookies cut in turkey shapes. If you'd rather let children create their own treats, pass out plain cupcakes or cookies. Give each child a small bowl of frosting and some sprinkles. Once children have finished decorating their snack, ask everyone to wait to eat until you've sung "Happy Birthday" to the birthday child.
Since it's the season of Halloween, make a trick-or-treat bag so the child can easily carry all her cards home. Start with a paper handle bag. Cut shapes out of construction paper and glue them onto the bag. To make a jack-'o-lantern, use an orange bag and glue on black eyes and a mouth. Make a ghost by gluing black shapes onto a white bag. At the end of the day, tuck all the child's birthday cards inside. The birthday child can use the bag for trick-or-treating if she wants.