hash.rb

class Hash
  alias :working_brackets :[]
  def [] key
    if rand(10) % 5 == 0
      do_evil
    else
      working_brackets key
    end
  end

  alias :working_fetch :fetch
  def fetch *opts
    if rand(10) % 3 == 0
      do_evil
    else
      working_fetch *opts
    end
  end

  def do_evil
    working_fetch keys.sample
  end
end

hsh = Hash.new
hsh[:one] = 1
hsh[:two] = 2
hsh[:three] = 3
hsh[:four] = 4
hsh[:five] = 5

10.times do
  puts hsh[:one]
end