Eddie Campbell points out that someone has posted the entirety of Luigi Serafini's Codex Seraphinianus on Flickr. What's the Codex Seraphinianus? I didn't know either, but I'm wondering how I went this long without hearing of it. Here's John Coulthart's description of the Codex from his essay on the topic:

"The Codex Seraphinianus is unique in placing its invented world centre stage and, even more uniquely, purporting to be a product of that world itself. Its creation seems the inevitable result of a trend of fantasy writing that delights in invention purely for its own sake, particularly invention that goes to great lengths to seem authentic or authoritative, academic even. The great precursor here is Borges’ short story ‘Tlön, Uqbar, Orbis Tertius’ which relates the invention of a Britannica-style encyclopedia describing with the greatest detail and authority a completely fictional world. Typically for Borges (as for Harrison), the story is also a commentary upon this kind of invention, as well as the effect it can have on our “real” world—for Borges and Harrison reality is more mutable than people like to think. Luigi Serafini takes the whole game a very difficult step further, by creating a complete work which describes his own fictional world in detail, with numerous colour illustrations and the whole written in a completely invented language and alphabet."

Looks like print copies can be had here, and I'm strongly tempted to pick one up. This stuff looks fantastic.