PirateBox is a…

“self-contained mobile [wi-fi] collaboration and P2P file sharing device. Simply turn it on to transform any space into a free and open P2P file sharing network. […] the system is purposely not connected to the Internet in order to subvert tracking and preserve user privacy.”

“Can I make my own PirateBox? Absolutely! The PirateBox is registered under the Free Art License (FAL 1.3). It can be built for approximately US $100.”

No storage of its own, apparently, so it’s only a conduit. Possibly useful for academic symposia and conferences that don’t want to pay venues for fast wi-fi just to let people swop big files? And perhaps for business meetings where attendees want secure (I’m assuming the box does best-quality wireless security) sharing of sensitive files.