Remember that rolling egg of joy, the Sony Rolly? It will soon roll its way into Japanese shelves once again, now wearing black. For those who aren't yet acquainted with this gadget, the Rolly is an egg-shaped MP3 player that dances and grooves to the music it plays, using its gyros and components that are sensitive to a song's beat, rhythm, and pitch.

Previously released in white, the Rolly now sports a sleeker black, and its arms (flaps? wings?) can be replaced with colored replacement arms to give your diminutive sing and dance robot a little zing. Fun, yes?

Those interested in plunking a hefty US$ 400 for the Rolly may want to know that it will be available starting April 19 in Japan, and that the replacement arms will net an extra US$ 15. Sure, most people may prefer a portable music player that sits still in their pockets instead of rolling on the floor and tripping people up in the process, but if you've got cash to burn, why not get one for a conversation piece?