Griffin AirCurve

The AirCurve from Griffin is old school. The clear polycarbonate stand amplifies music from your iPhone acoustically—as in, no electricity, no speakers, just the curvature of its mold. It works shockingly well, giving your iPhone a 10-dB boost. Unfortunately, the iPhone speaker itself produces a trebly, tinny sound and there's no shape in the world that can help pump up the bass. This makes the AirCurve a great way to amaze your friends and a convenient way to increase the volume on conference calls, but for turning your iPhone into a real sound system, you're going to need something that requires batteries or a plug.