You can make it a luau. Easiest ever. Everyone comes in Hawaii theme. Get flower leis and tape up streamers everywhere. Luau music form a used CD on Ebay.
They have 97 cent metal pails at Walmart. They are small and you can get puffy paints for them to decorate or you can do it for them. Let them dry in the sun and save them for desert.
Make a giant worms in dirt recipe and give them the pails to take their servings in.mud desert recipe.
http://www.thatsmyhome.com/recipes-for-kids/worms-in-dirt...
Get a large clear plastic bowl so they can see the layers. Put gummy worms in them and stick flowers in the top like it's a plant. Later, they can use a plastic shovel to get desert.
Toss in a palm tree bounce house and you're set.