Is this the smallest MP3 player around? Probably not, but the Cool Motz MusicBox Core is certainly one of the quirkiest.
But this acorn-shaped MP3 player does actually do a job, packing in 1GB of storage, USB connectivity, MP3, WMA and OGG playback, joystick control for volume and track search as well as a li-polymer battery that promises up to eight hours on a single charge. All that from a player sized at just 38mm x 30 mm.
Available online from Korean retailers, where it sells for the equivalent of £30.
Retailer site (via Nexus 404)