Waterproof cases are nothing new, but The Joy Factory's RainBallet for iPhone 4 ($50) takes an interesting -- albeit limiting -- approach. Two hard plastic halves are attached by a hinge at the bottom, and the iPhone 4 fits comfortably inside. To lock the case there are three screws, meant to be turned with a "Use Me to Lock" emblazoned coin included with the case. Once closed, the case claims to protect against splashes and sprays of water, but not…
