From the cool-looking-but-totally-impractical department comes this Rubik's Cube MP3 Player concept. Look, it's a Rubik's Cube! And it plays music!
It's neat and all, being controlled by twists of the columns, but who wants to carry around a Rubik's Cube in their pocket? And I prefer my controls to be something I don't have to think about, not something I need to think extra hard about. Somehow I think this will stay a concept for the foreseeable future.