The British Library have made 15 of their most valuable books (and one belonging to Bill Gates) available to browse through interactively. The company that have helped them with this, Armadillo Systems, will be using the toolkit they've developed to work with other libraries and museums to make valuable and fragile materials available for common oiks like us to gawp at.
You can go straight to the application, or read more about it. The blog article is by a Microsoft developer, Tim Sneath, who worked on the underlying Windows Presentation Foundation (part of .NET 3.0), so it is showcasing the technology, but it does that by highlighting what the application has to offer, including some navigation hints.
I would have liked to be able to zoom in still closer to the page before the pictures get grainy, but that's not a major complaint, and I expect it would have had significant performance implications.
Tim Sneath's name may be familiar to some of you; apart from working on WPF he was a regular presenter at MSDN Roadshows in the UK before moving to Redmond, and he helped put us in touch with the right people for Insights to take part in the "Ascend" program for early adopters of Visual Studio 2005.
Edit: For the .NET-deprived, there are Shockwave versions and plain old HTML - but you're missing out.