Microsoft is currently suing Apple over the page turn on the iPad's ebook reader. They have a patent on the idea of using a page turning gesture to go to the next page in a book on a computer, together with the idea of showing a page is turning.

No code, no description of how to render it - just the idea of taking an everyday action (turning over a page) and using it to do the same thing on a computer

http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sec...