Recipe: Working w/ Feeds, and creating custom Parsers and Processors

I'm currently building a Feeds: Meetup module that can import event data from Meetup.com. Can almost be done with feeds out of the box, except it doesn't interpret the data quite right and doesn't provide a good option for unique identifier.

I've written kludgy modules before, this is my first time writing one with code that's meant to be seen. Documenting the process and will expand into a recipe!