Mike Pearl presented a great meetup on Creating Content Plugins for Joomla on May 1, 2013 for the group. Thank you, Mike!
Get the zip package of slides and exercises used for the meetup. Mike has uploaded the zip file to meetup on our group page under Files as an alternative method to getting it.
You may need to follow the instructions for the prerequisites in the description for the Creating Joomla Content Plugins meetup in order to do anything with the zip package.