Pretty cool Interactive Display Window #retailinteraction
via youtube.com
+info: http://berglondon.com/blog/2010/11/03/media-surfaces-incidental-media/ You also can check this other color sensitive interaction
Some months ago an smart installation near fitting rooms was built by Diesel Spain, called DIESEL CAM (Check it out: http://tiny.cc/66cft )
People tried clothes and could share a picture on their Facebook Wall in real time. In this case I would have put the camera inside the fitting room and add a skype option to manage direct influence from your peers.
Similar to Diesel's idea was launched recently by LBi NY, but they made the whole process easier although also virtual. Installation don't need a cam because you try clothes virtually.
Face recognition changes the product offer based on gender and age