Oh I see. I think the best answer to your question is the Hack example site https://github.com/hhvm/hack-example-site. It contains the source for the Hack site along with build instructions.

Although it's not an MVC site, they do a lot of inline HTML ...

Yeah, almost everyone in the real world is using it via FastCGI. People have a huge investment in the configuration and operation of their existing http server (nginx or apache).

I work at Facebook as well, but mainly in JavaScript so I haven't done a lot of PHP either :)

You could use a common PHP framework like FuelPHP, Laravel or Kohana. I'm not sure which frameworks are 100% compatible with HHVM, but I think they're all getting quite close to 100% (or may even be at 100% with the 3.0 release). It's fine to mix PHP and Hack in the one project, so you could use a PHP framework and use Hack just for your code.