I found a great site today on interactive architecture.
They had a funny article with video clip about a project at the MIT Media Lab on an interactive urinal. The combination of the virtual with the physical is what intriqued me the most. The stream producer was able to fire the stream at different areas of the backsplash in an attempt to hit the corresponding images on the video screen.
Take a look at the video, don't worry you won't see anything objectionable.