For the past couple of years, I've always carried one of those miniature fold-up flash drives on my key chain. It's invaluable for those moments when then internet is broken and the world will stop turning if you don't transfer those photos and that slide deck right the hell now. But if that flash drive would also serve as an emergency phone cable, I would be the happiest geek on the internet.
The Sparrow is a crowdfunding project for a flash drive/phone cable that clips onto your keychain. The design is brutally simple -- the cable is short, and the connectors at both ends house magnets, so when not in use, it can be clipped through the keychain. The flash drive comes in 16GB, ($US35) 32GB ($US49) and 64GB ($US79) versions, with microUSB and Lightning connectors available on both.
The other neat benefit (for the Android version, at least), is that the flash drive can be accessed from your phone, which helps with file transfers, or storing your overwhelming back catalogue of selfies.
The project is currently on Indiegogo, and as such comes with the usual crowdfunding caveats that it's not a real for-sale item yet and quite possibly never will be. I also have reservations about the magnetic closure system -- bad visions of a stupid-expensive phone cable getting knocked off when I force my keys into a pocket, to be specific. Nevertheless, if all the bugs get ironed out, this thing could definitely find a home in my pocket. [Indiegogo]