I would hesitate to suggest anything crazy. Some people that I know do things like take lots of laxatives (it relaxes your muscles "down there", and in fact there are warnings on most laxatives that pregnant women should not take them without consulting doctor as it may cause miscarriage--but your wife is too far along for "miscarriage" per se). But it's not good for the baby or your wife to do any crazy home remedies like this--could dehydrate your wife, etc, etc, etc. Just not a good plan.
I think let nature take its course, and if nature isn't quick enough, then demand that the doctor induce her. I hate to say what I"m about to say because then I'll become one of those ppl who tell horror stories to expectant parents, and I never want to do that, but....my sister in law went too far past her due date. The doctor kept delaying inducing her, delaying inducing her, delaying inducing her. The baby wound up dying because it was inside for "too long". She had to have a c-section to remove her dead child. The doctor was devastated, as were my brother and his wife. So be pushy if you have to, but don't let it go too far, know what I mean? (no they did not sue the doctor, as they are religious and felt that if the baby wasn't meant to die, the baby wouldn't have died)