I’ll tell you what. Fill a city with these things, and I’ll move there. I can’t think of a greater source of childish delight than a playground full of these things, haphazardly zipping around the asphalt, attracting the attention of every bird, dog, and blogger that passes by.
What’s happening is there’s a solar cell in there that charges a small battery. When the battery achieves a certain level of power, it discharges, driving the wheels and rolling the ball. A clever layout of rods and rollers inside ensures that the solar panel is always pointing upwards.
It serves as little purpose as anything I’ve ever seen, yet now I can’t imagine a happy world without it. And I love the fact that if suddenly all humans were eliminated from the earth, these little guys would keep on rolling until the sun exploded.