bouncing on an exercise ball for 30 min. sent me into labour 1 hour later. Sex didn't work for me but it may work for you.
oh or nipple stimulation...15 minutes on each nipple each hour for several hours.
supposedly evening primrose oil can be used...you can rub a 500mg tablet 3 to 4 times a day on your labia or on your cervix if you can reach it. this is said to induce labor but it is unclear whether or not it actually helps or not.