Showcase of beautiful typography done in TeX & friends

If you were asked to show examples of beautifully typeset documents in TeX & friends, what would you suggest? Preferably documents available online (I'm aware I could go to a bookstore and find many such documents called 'books'). Extra bonus for documents whose LaTeX source is available.

This is not an idle question. Seeing great examples of any craft is both educational and inspiring, let alone explaining why we prefer TeX to Word or other text editors.

For instance, I like how Philipp Lehman's Font Installation Guide looks. I don't know enough LaTeX to realize how much customization was done, but the ToC looks polished.

Your nominations, please ...