Refactor .each where each is redirected into a hash
I think this is where you are trying to get to:

class Busy
  def event_info
    {
      :id =&gt; id,
      :title =&gt; title,
      :start =&gt; busy_start_time(start_date, start_time),
      :end =&gt; busy_end_time(end_date, end_time),
      :allDay =&gt; false,
      :recurring =&gt; false,
      :color =&gt; 'black',
    }
  end
end

@events = @busy_items.map(&amp;:event_info)


Some additional notes:


There is no need to initialize @events to an empty array, favor expressions over statements with side-effects (map, select, reduce and so on, instead of each).
I renamed the variable to busy_items to emphasize it's a collection.
Busy does not sound right for a class name. Classes are usually nouns, not adjectives. What's the nature of this class?