I thought this ingenious invention might interest some folk on here:
The SunSaluter is a solar panel rotator designed for the developing world. Using only the power of gravity with a water clock, the SunSaluter enables a solar panel to passively follow the sun throughout the day, boosting energy output by 30% and producing four liters of clean drinking water.
If only we managed to put some electricity generator there somewhere, we could avoid the trouble of having to fill that water bottle every day…