I don't know how many of you can get to Maine before June 5th, but Bowdoin College in Brunswick has an amazing exhibition of pop-up books. Here's a video about the exhibition and a little of the history of this wonderful fusion of art and book (warning, plays a little background music and is narrated):
Bowdoin is also offering an online tour of the exhibition here.
Video credit: Pop-ups! They're Not JUST for Kids from Bowdoin College on Vimeo.