Remember the Micro Windmill charger which uses wind to charge a mobile phone, here is something similar. From Gakken Japan comes the Personal windmill kit which has everything to make your own windmill. It is very basic and fits on the top of a plastic bottle which prevents heavy winds from knocking it down. There is no battery to store the power but it does have an LED which lights up when the windmill is in motion. Nothing groundbreaking but cool once you make it yourself. Available in Japan only for 2300 Yen ($22).