Project:Kinect Robotic Arm
From London Hackspace Wiki
The idea here is to have an intelligent Robot Arm that is able to find and pick objects, not using a pre-determined sequence of steps nor some kind of remote control, but instead use Kinect sensor to find the objects to pick.
Later one could add some wheels to it - with a mobile platform, this would in fact be converted into an autonomous robot. The Kinect would also be used to detect and avoid obstacles.
In terms of usefulness, although it doesn't really have to be useful, as it is so cool, it could be used to pick lego parts that might be spread on the floor and put them into a box.
Hardware
Robot Arm Kit - 6 DOF
(includes the SSC32 Servo Controller) Kinect Arduino Uno Raspberry Pi