Researchers at Tufts have a single molecule that acts as an electric motor – a tiny little armature and pivot:

The motor, made from a single molecule just a billionth of a metre across, is reported in Nature Nanotechnology…The butyl methyl sulphide molecule was placed on a clean copper surface, where its single sulphur atom acted as a pivot.

Its primary applications so far are a) driving the next generation of “Smart Car”, and b) powering the printer in Tom Bakk’s office.