Interesting site layout

I was recently given the task of creating the webpage for my school’s physics department. I want to recreate a textbook where you would actually have to flip the page to get to the next section. While searching the net, I found exactly what I was looking for.

link

How on earth can I recreate that effect? I know it has somethning to do with rotations and dragging a mask with the mouse but how? I’m totally lost. Any ideas would be very helpful.