http://blog.nilsjonsson.com/post/562328378/throw-a-wrench-in-the-works

poor_tevye.rb

require 'tevye'

poor_tevye = Tevye.new
result = catch(:miracle_of_miracles) do
  poor_tevye.live
end

tevye.rb

class Tevye
  
  def live
    sunrise
    sunset
    l_chaim!
    toil_in_anatevka
    :pauper
  end
  
  def rich_man?
    false
  end
  
private
  
  def method_missing(method, *args)
    nil
  end
  
  def toil_in_anatevka
    if self.rich_man?
      throw :miracle_of_miracles, 'Emigrated to the Cayman Islands'
    end
  end
  
end