Forget the Gym

Don't waste your money anymore on those high-priced gym memberships - here's a better solution: go to the grocery store with two or more children.

Need strength training? Grab one of the surplus Army tank shopping carts and load up your kiddos (right away you're likely moving 75+ lbs.); then go up and down all aisles while stocking your cart.
*** Extra credit - go to Sam's Club where everything is industrial size ***

Looking for an aerobic workout? Let your kiddos (to truly get a workout there must be at least 2 children without any type of tethers or leashes) walk with you through the grocery store. To guarantee that you meet your maximum heartrate, walk through the cookie/candy/treat aisle.
*** Extra credit - go to Wal-Mart where you are not only sure to forget something and crisscross the store numerous times, but the Wally World Time Warp assures that you will be active for an adequate period.

Don't have kids? Borrow some from a poor, tired mother and consider it multitasking: exercise, shopping, good deed.