This is exciting stuff. Finally! This is very similar to the namespace approach I and other proposed long ago. The key difference being #using to active the patches. Based on those old ideas, I wonder if the #refine method is actually necessary. Would this not do as well?

  module TimeExtensions
    class Fixnum
      def minutes; self * 60; end
    end
  end

  class MyApp
    using TimeExtensions

    def initialize
      p 2.minutes
    end
  end