Request for Clarification/Additional Documentation around Handlers, Email Notification

I spent several hours today trying to wrap my head around Handlers and get failure event notification over email working. There are a couple of examples out there, but they all assume a rather high level of understanding about things, especially around where certain configurations should go (in which file, etc).

I got it working with chef_handler, but I basically pieced together stuff from the chef handler documentation, as well as various other places on the internet.

A fully functional, detail walkthrough of how to configure email using chef_handler would probabaly be extremely useful for a lot of people, and especially n00bs to Chef like myself. I'm gonna document my configuration in a Gist and I'll link to it here if it's useful.

Start by reviewing the existing Handler and chef_handler documentation and examples referenced by the request. Document a complete email notification setup, including which configuration belongs in each file; done means a newcomer can follow the walkthrough to receive failure event emails.