This is an old wives tale. The fact of the matter is, labor starts when the baby is ready and not before.
You can try walking, spicy food, sex, nipple stimulation, castor oil, etc. And if you do go into labor, you might think it was because of something you tried - like, say, the sex. But it would be sheer coincidence. Your body will only go into labor when certain hormones are produced. Hormones that are created by the baby.
I know the end is hard. Try to get some rest and unplug that darn phone so people will quit calling to remind you that you haven't had the baby yet.
This is why it is called an estimated due date and not an actual due date.