That battery you're throwing away may not have enough energy left to power your gadgetry, but it does have enough juice to light up a low-energy LED. That's the driving idea behind South Korean designer Sung Woo Park's conceptual Energy Seed, a stylish street lamp powered entirely by discarded batteries.
Drop a battery into one of the Energy Seed's disposal holes and it'll fall down into a tube. Several batteries can be stacked one on top of the other, daisy-chaining drained batteries into a long-lasting power supply for an LED lamp that will give pedestrians a bit of light on the sidewalk. It's a great way to re-appropriate trash that we'd otherwise consider useless.