The DUO Atom cellphone from Korea not only supports two SIM cards, it also boasts an integrated gravity sensor that lets the handset know the right side up. The reason behind this is a no-brainer - in order to know which account will be used, the phone must be rotated the right way up. A change in orientation will automatically reverse the screen and keypad to the other phone account, assuming two SIM cards have been inserted. Pretty neat, eh?

Source: Crave