monkeypatch.rb

# ==================
# Spell: Monkeypatch
# ==================

# Change the features of an existing class.

"abc".reverse # => "cba"

class String
  def reverse
    "override"
  end
end

"abc".reverse # => "override"

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