class Attendee
  def listen
    puts "think: interesting stuff ..."
  end
end

module Tweets
  def listen
    super
    puts "tweet: great conference! :D"
  end
end

module Applause
  def listen
    super
    puts "applause!"
  end
end

attendee = Attendee.new

class Attendee
  include Tweets
  include Applause
end

attendee.listen

# think: interesting stuff ...