Chinese designer Daizi Zheng created a conceptual mobile phone for Nokia that could be powered by cola. The idea is the phone could run on a battery that uses enzymes to generate electricity from carbohydrates.
A bio battery is used instead of the traditional battery to create a presumably pollution free environment. Unfortunately the idea bounces back in your face once you calculate the energy required to produce a can of cola. But there is hope, as it won't require 'the real thing' to charge your phone. It will also charge on sugar water.
Besides the benefit of having a fully biodegradability battery, the notion of having your electronic appliances run on the same energy sources as yourself is stimulating, to say the least.