gistfile1.rb

module Minimal
  module Tidy
    def to_tidy
      pipe = IO.popen("tidy -q 2>/dev/null", "r+")
      pipe.write to_s
      pipe.close_write
      pipe.read
    end
  end
end

class String
  include Minimal::Tidy
end

p"<p>blah?<p>".to_tidy