Send the campers home with a small backpack filled with mini-flashlights, freeze-dried camp food, compass, comic books, camping supplies, glow-in-the-dark stickers, water toys, etc.
Alternatively, have the kids enjoy one more parting activity ─ panning for minerals and stones. Purchase an assortment of rocks, stones, and minerals and hide them throughout the party area. Right before the kids depart, provide them with brown paper lunch sacks and have them search out the stones to take home with them.
You have the entire evening to take pictures of the kids having fun during the campout. Remember to send the pictures to your party guests with your thank you notes.