Car is tiny, power source is very large. Unfortunately, solar cars are still in the research and development phase, until then this working miniature model will have to keep us entertained.

The world’s smallest solar powered car - it zooms along when the sun shines on the solar panel. No batteries - it gets its power just from the sun. No assembly required. Measures a tiny 3.3 x 2.2 x 1.4 cm. When the sun shines on the solar panel, the panel makes electricity that turns the motor and the wheels. A fun demonstration of solar power. Will also work when close to a strong artificial light source. Reported on ThinkGeek.