Number one is vegetable, fruit, herb juicing.
Nothing in world is as addictingly good for you as this.
Spinach/carrot/apple/garlic or a celery,carrot,beat/garlic drink is good stuff. Gotta clean up the mess afterward and this is a huge drawback for many as is the whole process of buying the produce, cutting it to fit in the juicer is just something that does not aspire a couch potato.
Second choice: creatine. Maybe you have to replace the starter on your car or maybe you have to spend a weekend clearing the overgrown oak trees on your property with a 28 inch chainsaw. Pound some creatine a for a few days before the big event and you'll come out feeling a good sore and ready for more!