Courtesy of our friends at Rocketboom
This idea just blew me away. A group of students from Germany are working on ideas to use trains as brief communicative platforms. As part of this "Moving Canvas" idea, the group have come up with 2 projects working in conjunction with each other called "Parasite" and "Parallel Worlds."
By attaching a purpose built case with a video projector installed to the side of a train, images are able to be projected onto the walls of subway tunnels as the train moves.
"The tunnels of a subway-system bear something mystic—most people usually have never made a step inside any of those tunnels. Confusing the routine of your train-travelling-journey, your habits and perception Parallel Worlds—making use of Parasite—allows you a glimpse into a different world full of surrealist imagery."
Should point out, attaching a strange box to the side of any form of mass transit in today's security-conscious world without permission from the relevant authorities is probably enough to get you dragged in to a dark room with large men in suits (in Australia, for 14 days without being able to tell anyone where you are). Transit cops aren't known for their sense of humour, or their anarchic or communal ceativity.