Roco

Roco is a robotic computer that moves its monitor "head" and "neck," but that has no explicit face. Roco is designed to interact with users in a natural way for applications such as learning, rapport-building, interactive teaching, and posture improvement. In all these applications, the robot can move in subtle ways that express its state and promote appropriate movements in the user, but that don't distract or annoy.

This robot was built for the Affective Computing Group at the MIT Media lab. The group is using the robot to implement a system that has the ability to recognize states of the user and also to have subtle expressions. (from http://affect.media.mit.edu/projects.php?id=837)