p90x but I spread it out over 120 days to incorporate a separate core workout which includes some of the concepts in @drewski's link. I will also play hockey, swim, run, teach spinning classes, etc as part of an overall effort to lose weight. I dropped 40 pounds last winter and it made a huge difference. Trying to drop another 15-20 this winter. Plus, our neighborhood is putting in an ice rink on our tennis courts, and I will be the main ice prep guy, so there with be a ton of skating with a shovel before resurfacing the ice. The variety of tasty beers for fall and Christmas do hamper my weight loss....but they are sooo good!!!