Samsung have recently announced the release of the Samsung Power Sharing Cable. The idea is simple, have a cable that you can share battery power between devices. The cable has a Micro USB connector on each end, one to be plugged into the power source device and the other into the device needing power, which corresponds to the arrows on the cable, and charge.
Samsung have also create a Power Sharing App that you can set exactly how much battery you want transferred over (as a percentage of existing battery).
Video
https://www.youtube.com/watch?v=yQ-di724bOc
The cable currently retails for $19.99 USD or £15 GBP. Do you see a need for it? Will you be buying it? Let us know in the comments.