Written by Magnus Holm At RubyConf 2010 Shugo Maeda talked about Refinements: A proposal for a new feature in Ruby which allows you to easily override methods without affecting other parts of your program: module TimeExtensions refine Fixnum do def minutes; self * 60; end end end class MyApp using TimeExtensions def initialize p 2.minutes end end MyApp.new # => 120 p 2.minutes # => NoMethodError L