An experimental documentation project by Johan Falk called Skill Compass has many Resources for learning Rules, including a skill building tools and related information on many topics.
09-2011 The Rules Way of Life, DrupalCity Berlin 2011
Learn content access, Rules integration (Screencast) - July 2011
Commerce, Rules, and Stock: Demonstrating the Power of Rules (Screencast) - July 2011
There must be Rules! DrupalCon Denver - 2012 (see also http://blip.tv/drupalcon/rss/itunes )