Here are also some of the things my users have created: http://gofoldit.com/gallery

It turns out that print design is quite behind technologically in a few areas, and providing clients with an interactive demo of what a folded brochure was gonna look like is one of them. I was told that the current state-of-the-art in this area was to print out a Black-and-White version of the PDF, to fold it, and then record a video of it being unfolded and emailing it to the client.