All of the following failed for us:
Sex
Curry
Fresh pineapple
Acupuncture
EPO
Kerb walking
Regular walking
Acupuncture
Wearing my best undies hoping my waters would break
Ditto for brand new bed sheets
Nipple stimulation
Watching all of our scan videos back to back
Beer
Clary Sage Oil
Shiatsu
Going for a drive up to high altitude

BUT we don't have a bath, so we didn't try that. Do it when someone else is home though, so you don't get stuck.