This guy (Michael Teeuw) has built something fantastic: A magic mirror. Like the one in Snowwhite, but without the face. There was one approach prior to this one, thanks to Pierre Rafast but it was very slow. The system consisted in an Rpi connected to a webcam and a monitor. While the webcam registered what was in front, the Rpi could recognice the face, display sometring and talk. But due to the power needed, there was some lag between reality and the image displayed, so it is kind of weird.