When the caller is a person whose number your cell phone recognizes, the cell phone turns into a picture of the person who's calling.
I don't mean "displays" a picture of the person's face on the screen. I mean renders it in 3-D, with the cell phone shaped like a little doll with screens wrapped
completely around its head and torso. Turn the cell phone around and you can look at the back or side of the person who called you. It's cute!
Obviously, requires some prior preparation from you: you must take all the appropriate front/side/back pictures of your friend and run them through a commercial software package to make a 360-degree smoothable view. Then upload this to your cell phone.
(Don't tell me they already have this in Japan.)