class DoNotDisturb
  def initialize
    @desk = InformationDesk.new
  end
  
  def method_missing(name, *args)
    unless name.to_s == "emergency"
      hour = Time.now.hour
      raise "Out for lunch" if hour >= 12 && hour < 14
    end
      
    @desk.send(name, *args)
  end
end

# At 12:30...
DoNotDisturb.new.emergency # => "emergency() called"
DoNotDisturb.new.flights   # ~> -:37:in `method_missing': Out for lunch (RuntimeError)