Efficient method to peel raw potatoes
There are electrical devices using a tumbler:

http://www.amazon.de/Melissa-646120-Kartoffelsch%C3%A4lmaschine/dp/B0079X0EQ6

(The German name is "Kartoffelschälmaschine" for anyone who wants to research it and doesn't like to read encoded URIs ;)

Interestingly, they are uncommon in the US judging by the amazon offers there- instead, the US knows a lot of electric versions of the "apple peeler/corer/slicer" design (which could probably peel a potato too if it was reasonably round, or a certain amount of waste is accepted).