Setting up Mac as local web server

A good while back, a friend set up my computer as a local web development server.

He didn't use MAMP. He modified a few files so that I could modify the /etc/hosts file and type in example.local and it would serve up the files located in my Sites/example.local/public_html folder.

Any ideas on what he did to make this possible? I can't get in touch with him, otherwise I'd just ask him