Example WP Cron job

wp-cron.php

<?php

// On the scheduled action hook, run a function.
function my_cron_job_function() {

	// Put all your codez here
	// Sample code fetches a json feed and caches it by saving it as a file
	set_time_limit(0);

	//File to save the contents to
	$fp = fopen ('cachefile-dos.json', 'w+');

	//The URL to the json feed you want to cache
	$url = "http://ip.jsontest.com/?callback=showMyIP";

	//Here is the file we are downloading, replace spaces with %20
	$ch = curl_init(str_replace(" ","%20",$url));

	curl_setopt($ch, CURLOPT_TIMEOUT, 50);

	//give curl the file pointer so that it can write to it
	curl_setopt($ch, CURLOPT_FILE, $fp);
	curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);

	$data = curl_exec($ch);//get curl response

	//done
	curl_close($ch);


	// For debugging - send yourself an email when cache rebuilt
	//mail("person@domain7.com","Project cache file was rebuilt","The project cache file was rebuilt");
}
add_action( 'my_cron_job', 'my_cron_job_function' );


// Schedule the Cron job with WP Cron
// On an early action hook, check if the hook is scheduled - if not, schedule it.
function setup_cron_schedule() {
	if ( ! wp_next_scheduled( 'my_cron_job' ) ) {
		wp_schedule_event( time(), 'hourly', 'my_cron_job');
	}
}
add_action( 'wp', 'setup_cron_schedule' );

?>