time_duration.rb

# timeit { sleep 20 }
# => {:weeks=>0, :days=>0, :hours=>0, :minutes=>0, :seconds=>20}

def timeit(&block)
  mul   = [604800, 86400, 3600, 60, 1]
  values = [:weeks, :days, :hours, :minutes, :seconds]
  units = []
  started = Time.now.to_i
  yield block
  ended = Time.now.to_i
  total = (ended - started).to_f.round
  
  mul.inject(total) do |t, m|
    units << t / m
    t % m
  end
  Hash[values.zip(units)]
end