I went to 42 weeks before being induced. I'm impressed by cupcakefairy making it all the way to 40+16!
I'd been having Braxton Hicks for a good couple of weeks and they were getting more intense.
I tried everything (exercise, pineapple, raspberry leaf tea, sex, acupuncture) in the last two weeks to get things going but nothing worked. I had a sweep at about 41 weeks but again, nothing.
I had the pessary at 6pm Friday night, by 9pm I was in full on labour and DS was born at 7am Saturday morning. The labour was very quick, very intense and ended up with DS being delivered by ventouse as they were concerned about his heart rate and would only let me push for 40mins. I didn't lose my plug until well into the night, and I think they actually broke my waters at some point...can't really remember!
Overall, it was quite a traumatic labour as it all happened so quickly. Inductions can be like this sometimes, or they can take forever. However, it was good that they were monitoring DS constantly as the cord was round his neck, hence the heart rate issues.
Be aware that if you have an induction you'll probably go under consultant care (it was the case in my hospital, others may be different) which meant that I couldn't have the birthing pool. Also, due to the monitoring, I felt like I couldn't have the active labour that I'd wanted as they really wanted me to stay on the bed the whole time. My DP was fantastic at being my advocate and chasing people up and finding out what was going on...although he did do a runner when I threw up! 
Good luck! It's really not long now, and you'll be holding your baby. Believe me, that is well worth all the pain and stress.