Reference 

S.S. Intille, V. Lee, and C. Pinhanez. Ubiquitous Computing in the Living Room: Concept Sketches and an Implementation of a Persistent User Interface. Proceedings of UBICOMP 2003 Video Program, 2003. 
[PDF] [Video (MPEG v1 AVI)]

Abstract 

This video shows some concept sketches of applications that might be created for a living room with ubiquitous display and laser pointer interaction technology. A fully-functioning prototype of a persistent interface is also described: a language-learning tool.

Keywords 

Ubiquitous computing, user interface, persistent user interface, language, learning, laser pointer interaction, computer vision.