Alvaro Cassinelli, University of Tokyo, has created a fascinating new technology called the Khronos Projector. "The Khronos Projector is an interactive-art installation allowing people to explore pre-recorded movie content in an entirely new way. By touching the projection screen, the user is able to send parts of the image forward or backwards in time."
I created two custom time-lapse videos for him and he has processed them with his technology and included them as part of his demonstration.
A thorough technical description (and many more examples) can be seen at
the Khronos Projector web site.
Here's a quick video explanation from Siggraph 2005 that's posted on YouTube...