For a memorable birthday party, invite your children's friends to a camp out in your backyard. Send out tent invitations, made by cutting shape's out of brown craft paper of grocery bags that form triangular tents with fold over flaps. Glue a contrasting triangle of green construction paper printed with the date and time of the party.
Party favors can be nylon bags filled with camping gear, like tiny flashlights and toy binoculars.
Trail mix is a great treat. Have sleeping bag races. Use mess kits to eat cake. Create a safe fire with a fake flame by using rocks, logs, and cellophane in yellow, orange, and red. Use graham crackers and chocolate bars, then use marshmallow fluff for the marshmallow that are flame toasted.