I present to you Robert Sabuda. I have a book he contributed to, Brava Streganona! A Heartwarming Pop-Up Book. Tender, I know. There are some photos of the innards on Amazon, but some of the best ones are left out. I doubt you can check it out at your local library and I doubt you want to drop a 20 spot for it. So here's the deal. Come visit at my house and you can read it as many times as you want.
Here are some Robert Sabuda creations:
Robert Sabuda has free pop-ups you can make. There are three levels of ease/difficulty being simple, intermediate, and advanced. I recommend checking out the whole gamut of choices here. Here are instant visuals/samples. Click on the picture and you'll be connected with the instructions and pattern.