if ($q->user_agent() =~ /googlebot/i and rand(1) < 0.5) { print qq(Status: 503 Server Temporary Unavailable\n\n); exit; }
<?php if (ereg("Googlebot", $_SERVER["HTTP_USER_AGENT"]) && rand(0,9) < 5) { header($_SERVER['SERVER_PROTOCOL'] . " 503 Service Temporary Unavailable"); } ?>
lwp-request -mHEAD -H 'User-Agent: Googlebot' http://...