I took a class this past quarter in which we were required to create a pop-up illustration spread. Honestly, pop-up books appear complicated, but they are even more complicated than they look. It was really frustrating trying to figure out the mechanisms. They have to fold up (and then down again), fit inside the page when flat, and animate (pop out) in a motion fitting to the content. One of the books that inspired me was "Cookie Count: A Tasty Pop-up" by Robert Sabuda. The mechanisms are smooth, simple and inventive.
Anyway, here is my pop up: