For completeness here are some additional links for the "similar" web application environments provided by other languages listed in the post title:
* WSGI (Python) - http://wsgi.org/wsgi/
* Rack (Ruby) - http://rack.rubyforge.org/
* Plack/PSGI (Perl) - http://plackperl.org/
* Ring (Clojure) - https://github.com/mmcgrana/ring
* WSAPI (Lua) - http://keplerproject.github.com/wsapi/