ePub sounds fancy, bleeding edge even, doesn't it? Who ever knew it was just a bunch of XHTML and CSS in a Zip archive?
Well, that's all it is. If you'd like a sample ePub I marked up using vi (yes, the UNIX text editor!) and some old data about 19th century Prussian military units stationed in Potsdam, help yourself! It's hosted using Amazon S3, so availability shouldn't be an issue.
"This specification defines the OEBPS Container Format (OCF). OCF is a general-purpose container technology. This specification describes the general-purpose container technology in the context of encapsulating OEBPS publications and OPTIONAL alternate renditions thereof. It is however anticipated that the general-purpose container technology described herein will ultimately be used in other bundling applications."