I read about a swedish company that had developed a paper with a liquid display. Among the uses would be changing wallpapers. Sometimes I wish you could enter a suspend sleep mode, and wake up when all these things actually exist. On the other hand, if I had gone to sleep in the 50's and assumed we would be flying saucers by now, I wouldn't have been impressed.

The first product using something touted as based on e-paper was the Sony Librie, but it seems it didn't really take off. Not outside Japan anyway.