@nerd2ninja and I were talking about ruby recently and it reminded me of an iOS app I developed and never released (circa 2012) written in ruby using Ruby Motion.

I hadn't done much meta-programming up until this point.

      def included step
        steps << step

        # dark magic (:include is private) to keep our models DRY
        step.send(:include, Model)
        step.columns :progress => :integer,
                     :day_id => :integer
        step.extend(ClassMethods)
      end

The app was a positive psychology app called '21days'. It'd take you through 21 days of exercises (attempting to form habits) including mindfulness meditation, gratitude journaling, kindfulness exercises, reinforcing social connections, and future prompting. It was nearly finished when I stopped working on it. At some point I realized I didn't want to use it - it asked users to do a lot.