This is definitely on my to-do list; an exhibition of pop-up books from the 19th to the 21st centuries has opened this week at the National Library of Scotland. The Library's website gives a historical over-view with some illustrations to whet your appetite, and STV's news report has a short video showing one of the books opening out - into a paper model of Hogwarts! I think my favourite pop-ups are Jan Pienkowski's, Haunted House for example, though I don't know if there are any in the exhibition. I'll be popping over to Edinburgh soon to find out.
PS January 2014: I visited this exhibition last week and, yes, Haunted House is there.