First is a nifty magic mirror, presented in the video below (no horizontal, English version yet, sorry):
The mirror is actually a touch screen, a camera, and an algorithm that samples the camera feed 30 times per second. The algorithm looks for the original logo imprinted on the shirt in order to replace it with another logo (or even with a video), while changing the shirt's color at the same time. Once you understand it's marker based, the demo looks less cool.
On the other hand, Fraunhofer demoed a mobile AR technology, aimed to augment historic tourist attractions. In the future, using an application installed on an iPhone (or currently on a mini Sony Vaio), tourist will be able to examine the Reichstag or Brandenburg Gate and see them as they looked through the years.
The software recognizes the buildings, as well of the perspective of the shot and delivers the historical equivalent of the photo, covering the original. The rendering of the historical snap is done is real-time – so if the user walks around the building, the picture moves with him. The picture is sent to a server via the 3G network, which delivers the “Augmented Reality View”.
Views of the Reichstag just after the Second World War, during the separation of East and West Germany, or after the fall of the Berlin Wall are available. The user can scroll back and forth between the different time periods and short explanatory texts round off the offering. (source)
Fraunhofer presented the same concept for ancient Rome in SIGGRAPH 2008, but it seems their technology has matured since then.