Changing every half-hour or so – anyone up to crack the (probably) SHA-256 checksum[0]? :-)<p>[0] <a href="http://forums.xkcd.com/viewtopic.php?f=7&t=101043&sid=a1c7bf145ef1f3be91cd56a27372048d&start=40#p3301961" rel="nofollow">http://forums.xkcd.com/viewtopic.php?f=7&t=101043&si...</a>