Have you been in a situation where you really needed your iPhone and the battery has been really low or dead? So have I! This Ampware Crankcase is the solution. With this case you can charge your phone anytime and anywhere without plugging into the mains. You just simply open the handle and turn to generate power (a green light will indicate correct speed). If you crank for 2 minutes you can generate enough power to make emergency call or crank for 10 minutes to get up to 2 hours of general use. Its been designed well and its very strong and drop resistant. Prices start at $79.
[image from softpedia.com]