[unchaotic]

Some other random ones that I've used in the past :

http://www.cronmaker.com/

http://crontab-generator.org/

http://www.openjs.com/scripts/jslibrary/demos/crontab.php

http://htmlminifiers.com/cron-maker.php

http://cron.nmonitoring.com/cron-generator.html

https://crontranslator.appspot.com/

http://cron.schlitt.info/