Japanese manufacturer Landport has created an ingenious variation on the wind-up flashlight with the BunBun - a compact torch that can be charged simply by swinging it about in front of you. Once you extend the handle and bend it at the hinge, you can charge the built-in rechargeable battery by cranking the BunBun for 30 seconds. Just this short amount of charging will give you about 5 minutes of juice.
The BunBun eco light also comes with an attachable strap that not only makes it easy to attach the light to your backpack, but also makes it less likely that the light will fly loose from your hand while you're trying to charge it.
The flashlight measures 1.6 inches in diameter by 5.5 inches long (or 40 × 140mm) and weighs in at 3.4 ounces (or 97g). It's available in a total of four colors: pink, green, purple, and black. BunBun will be available sometime in April, and will cost about 2100 yen (about $22).
On a bit of a tangential note, this makes me wonder if it might be worthwhile to implement this sort of charging device into skipping rope handles. Maybe a BunBun skipping rope could be their follow up?