There is also a user-driven project to organize Wikipedia articles into books, although they currently just use the articles verbatim as chapters, which doesn't address things like redundancy between articles that makes sense when they're articles, but should ideally be removed if they were going to be printed as book chapters: http://en.wikipedia.org/wiki/Wikipedia:WikiProject_Wikipedia...
Here's an example one: http://en.wikipedia.org/wiki/Book:Compiler_construction
I have thought it would be a great revenue source for the WMF. Make little books based on certain articles like the List of Common Misconceptions. Sell them as impulse purchases near checkout counters in bookstores. Step 3, profit.
The fundraising team at the WMF isn't really into it, they don't want the hassle of making & distributing physical objects that may not even sell. But it would be a cool project for the right team -- maybe if you want to build your resume as a book designer.
In some ways that's the whole point of it being open-content, that you can reuse/repackage it in various ways, but there hasn't been a lot of creative third-party reuse yet.
By which I mean; if you pick a topic to turn into a book your likely to have articles of a wide range of quality (from featured status, the top, to stub, the bare minimum).
Couple that with potentially disparate styles of writing and it can become difficult to stitch several articles into a book form.
Not that people don't do it; the volunteer email support service regularly gets people complaining about the $50 "text book" they bought of Amazon simply being Wikipedia articles.
It's always been in the back of my mind to try and do something like it though; perhaps an "obscure topics" book with some of the more interesting articles put into it.
Maybe that will be my weekend project!