Acupuncture?
I tried all the usual tricks (pineapple, raspberry leaf tea, long walks, nipple stimulation, curries, climbing stairs, bumpy roads, sex) and not one worked. Didn't try acupuncture but know of a couple of people who went into labour not long after it.
Personally though, I think it's all down to chance when your baby chooses to arrive and nothing you do will alter that. If it arrives after 16 pineapples, well, it's just coincidence.
But then I'm very cynical having had 2 late babies who refused to budge!!