A recent patent filed by Apple shows the touchwheel/pad of the Macbook/iPod lighting up as you touch it. It covers both a light encircling your finger (as above), and also blocks of light as you move across areas (see below):
In addition, there’s a third option whereby intensity of light is decided by speed of movement of your finger. Of course, the question now is: what is the use-case for this? Is is interweb browsing in the dark, or some kind of Jean-Michel Jarre light piano?!
[Via: Mobilewhack]