The IOGEAR gadget charger is capable of charging mobile devices when they they run out. It comes with a built in Lithium Polymer battery and comes supplied with 6 adapters allowing for different devices to be plugged in. It costs $40 and is good for about 500 charges which should last you a few years as it is only intended to be used when your phone dies and you do not have a charger with you. On the front of the device there is a charge level indicator.
As much as I like my hand winding charger this makes life far more easier when the batteries die.
Via: MysticGadgets