The Cicret Bracelet ($TBA) allows you to interact with a projected image of an android interface right on your arm.
The bracelet is made up of a pico projector, a row of proximity sensors, an accelerometer and a vibration module. 16 and 32 GB are expected for storage options. It connects to the internet via wifi, bluetooth, and a mUSB port.
A twist of your wrist activates the projector which allows you to do most of the things you can do on your smartphone like reading emails, browsing the web, and playing games.
Right now the makers of Cicret are trying to raise enough funds to make it a reality. They expect the first prototype to by ready in the next few months.