PhysOrg reports about Sound Charge, a prototype of a t-shirt capable of charging your phone by absorbing ambient sound:
The shirts utilize ambient sound as a catalyst to produce electric voltage, and were rolled out just in time for the Glastonbury Music Festival in Britain. Developers hoped that the shirts would offer a convenient, eco-friendly way for festival goers to charge their phones while they're rocking out away from the grid.
The material used in the shirts is made from a product called piezoelectric film, which is capable of transforming sound waves into an electric charge via the compression of interlaced quartz crystals. Once that electric charge is generated, it is stored in a reservoir battery which can, in turn, be used to charge your mobile device.