singleton_method.rb

# =======================
# Spell: Singleton Method
# =======================

# Define a method on a single object.

obj = "abc"

class << obj
  def my_singleton_method
    "x"
  end
end

obj.my_singleton_method # => "x"

# For more information: http://www.pragprog.com/titles/ppmetr/metaprogramming-ruby