Alice in Wonderland pop-up book by Robert Sabuda. My best friend gave this to me for a birthday gift, and it's definitely one of the coolest things I own. The same artists has also done a Wizard of Oz Pop-up book.
Kirigami Pop Up Wedding Card with Template! Kirigami is the Japanese art of cutting paper and involves folding paper certain ways to cut out symmetrical forms. All you need to start is a good X-acto knife and some paper!