With a little over 2 months left in 2012, I challenge you to register for a organized walk or run (such as a 1 mile, 5K, 10K, half marathon, sprint triathlon, etc). The race doesn't have to be this year, giving you plenty of time to train if need be. Having a specific date in mind will help you stay focused with your goal of being healthy. Hopefully you will also gain a sense of pride and achievement when you complete the course.
Let me know what event you chose and when it is so I can cheer you on!