A computer mouse stocking-filler

How do you improve on the 40-year-old design we call the mouse that has, together with the keyboard, become the default tool for computer interaction? Patrick Baudisch of Microsoft Research and the Hasso Plattner Institute in Potsdam, Germany, has a Christmas-themed answer - stuff it in a stocking.

The user no longer needs a flat surface to put the mouse on. Instead, they massage the sock with one hand to rotate the mouse which is free to move inside while the material remains stationary. The mouse movement is rather like a bar of wet soap rotating in your hand.
The mouse's laser detects the motion of the sock going by, just as it would a passing mouse pad, and translate what it sees into onscreen action. Baudisch designed the "soap" mouse in 2006, and has since gone onto other computer-human interaction projects including lucidTouch and, as reported in nanoTouch.