tornadoweb.org is currently hosted on app engine (source code in the
website directory of the git repo), although now that it's 99%
sphinx-generated HTML we may move off of app engine at some point.
There's a mirror at
http://tornado.readthedocs.org, and while it's not
easily discoverable, they've been offering zipped html and epub
downloads at
http://readthedocs.org/projects/tornado/downloads/
I've just turned on pdf generation as well. It's a little wonky (the
table of contents is empty on readthedocs, although it works when I
build a pdf locally), but it mostly works.
-Ben