Get ready for WWDC.

cron.php

<?PHP
  $html = file_get_contents('https://developer.apple.com/wwdc/');
	
	if($html === false)
	{
		send_script_failure();
		exit;
	}
	
	preg_match_all('/2012/', $html, $mentions2012);
	preg_match_all('/2013/', $html, $mentions2013);

	$mentions2012 = count($mentions2012[0]);
	$mentions2013 = count($mentions2013[0]);

	if(($mentions2012 != 3) || ($mentions2013 != 1))
	{
		send_message();
	}
	else
	{
		echo "Everything's fine.\n";
	}
	
	function send_message()
	{
		for($i = 0; $i < 5; $i++)
		{
			curl_setopt_array($ch = curl_init(), array(
			  CURLOPT_URL => "https://api.pushover.net/1/messages.json",
			  CURLOPT_POSTFIELDS => array(
			    "token" => "<token>",
			    "user" => "<user>",
			    "message" => "WWDC tickets might be on sale!",
				"sound" => "siren",
			  )));
			curl_exec($ch);
			curl_close($ch);
			sleep(5);
		}
	}
	
	function send_script_failure()
	{
		curl_setopt_array($ch = curl_init(), array(
		  CURLOPT_URL => "https://api.pushover.net/1/messages.json",
		  CURLOPT_POSTFIELDS => array(
		    "token" => "<token>",
		    "user" => "<user>",
		    "message" => "WWDC script failed.",
		  )));
		curl_exec($ch);
		curl_close($ch);
	}

Hmm. We could also test to see if the MD5() of the $html returned has changed.

You can set up the same thing (a page content check) through Pingdom. They can message you through Twitter (DM if you follow their statusbot "pingdomalert") or SMS.

Pingdom documented a technique for last year's WWDC. For this year, I would recommend a check that tests for the presence of "wwdc2012-june-11-15.jpg" (the hero image shown there). If that is missing, chances are they've replaced it with the promo for 2013.

@bradchoate Nice call on checking for the image filename.