Even if you don't have a water feature on your property, you can celebrate the joys of boating, surfing or just an afternoon near the water with an under the sea themed party. Choose your favorite denizens of the deep, like whales, sharks and dolphins, for party ware and tablecloths. Add some unexpected surprises, too, like a treasure chest made from plywood or an old trunk. Have everyone bring a gag gift for the chest, and you'll be able to distribute the booty at the end of the evening. Decorate with shells, sand and candles. Asking everyone to wear costumes is always fun, but even if no one is wearing an eye patch, it's still a great way to throw a party.