We have seen all sorts of portable devices, and today we have a device that will allow you to play piano on almost every surface.
This unusual device comes from Japan and it is called Wrist-Mounted Finger Piano, and all that you have to do in order to turn any solid surface into a piano is to put the speaker on your wrist, and special "caps" over your fingertips and you're good to go.
Each time when you tap a surface with your finger, the Wrist-Mounted Finger Piano will produce a specific sound, however, since all notes cannot be assigned to five fingers, you also have three additional notes on the speaker.
In addition, we have to mention that this device can only play basic notes, so you won't be able to replace a piano, or similar device with Wrist-Mounted Finger Piano.
Wrist-Mounted Finger Piano is one weird device with basic piano functionality, and it currently costs about $40.
Source:
Japanese Wrist-Mounted Finger Piano is very portable | Ubergizmo (http://www.ubergizmo.com/2012/03/japanese-wrist-mounted-finger-piano/)