Plastic Logic has gotten investments of $100 million dollars to set up manufacturing for plastic electronics in Germany. The plastic electronics they are planning to build are flexible active-matrix display modules. Really, paper thin plastic that can be used as a display. The plan is to begin manufacturing in 2008.
The first thing to come to mind are e-books. People have been talking about them for years, but if you could carry an entire set of books to read with just one plastic sheet, they may become a reality. No one wants to read off a computer screen, but if you give them something that feels more like a book, you may have a winner. I was also thinking about other uses. First to come to mind could be a restaurant whose menus would be able to be changed on the fly, which may have more to do with me being hungry than being the most important application of this technology.