Got a kid with a summertime birthday? Well, you're in luck! Not only can you hold that party outdoors, we've got a load of fun summer birthday party ideas for you. I mean, you could just do a cake and let the kids run around for the afternoon, and I wouldn't blame you a bit. But a themed party is extra special -- and your kids can get in on the planning, too. Here are seven birthday party themes that are especially fun for summer.