El-E, the robot butler makes use of a unique interface that allows this robot to leapfrog other robots that depend on more exotic interfaces (like voice command recognition). The El-E (pronounced "ellie") robotic butler is under development at the Georgia Institute of Technology.
Charlie Kemp, leader of the research team at the Center for Healthcare Robotics in the Health Systems Institute, selected the hand-held laser pointer as the ideal way for humans to indicate the object of their interest to the robot.
"We humans naturally point at things but we aren't very accurate, so we use the context of the situation or verbal cues to clarify which object is important. Robots have some ability to retrieve specific, predefined objects, such as a soda can, but retrieving generic everyday objects has been a challenge for robots."
The El-E robot is intended to provide assistance to people with limited mobility. This unique helper robot has an omni-directional camera that can see most of a room at a glance; the robot moves toward the object "painted" by the laser pointer (see El-E robot video below).
(EI-E robot butler video)
The robot uses a laser range finder to scan across the desired object, and then uses a camera in its hand to visually distinguish the object from the background. A special gripper closes upon the object.
The closest thing I can think of to a robot butler is Robbie, from Forbidden Planet; Robbie had lots of additional functionality, of course, including the ability to synthesize and manufacture any object in quantity.