Elliptic Labs have designed a touchless 3D user interface: it detects finger movement in 3D without you touching the screen.
While the hows and whys are not explained, there seems to be a black pyramid that I am guessing does some sort of radar-like tracking of the finger tip. I wonder if we'd have to paint our fingernail?
In any case, the concpet suffers the same problem of all touch (or touchless, in this case) interfaces: the need to have your hand in the air, which gets tiring. There's a reason the keyboard and mouse remain popular -- gravity. (Probably the same reason TabletPCs are never popular.)
Meanwhile, Engaget reports on two new designs of mice:
-- Lite-On's Moldable Mouse takes whatever shape you want. I'd like that, because I find all mice to be too narrow for my liking. It uses lightweight modeling clay covered by nylon-polyurethane fabric.
-- Jelly Click is an inflatable mouse. Deflated, it's flat for travel; inflate it for use.