"The problem with handheld devices is that they have an annoying habit
of running out of juice at the most inopportune moments. There’s nothing
worse than being stuck on a train or a plane with a dead MP3 player or
handheld console, and if you’re embarking on a long haul flight that
scenario is often unavoidable. If only there was some way of recharging
your device, while continuing to use it – well actually there is."