Voltaic USB Touchlight
Odds are, if you have a smartphone, tablet, or multiple modern devices, you probably have one of those portable battery packs for on-the-go charging. Put it to good use when it's not in use by hooking it to the Voltaic USB Touchlight ($35). This waterproof USB light features a stylish silver body and a patent-pending lens that you tap on to cycle through three brightness levels. You can hang it like a pendant light — to light a tent or the underside of your car's hood, for example — or hook it to the included flex cable and use it pretty much however you want.