You don't need Gillian Michaels. You don't need P90X. Hell, you don't even need Richard Simmons!
What you need is three weeks off work, a sister moving into the three bedroom farmhouse you happen to have on your property and a desire to want to see your husband more often so you offer to help him landscape a bit.
Peeling wall paper will do wonders for your forearms as you chip away at decades of the stuff.
Rebuilding walls after you remove most of them removing said wall paper will do wonders for your shoulders as you lift bags and bags of plaster.
Patching and painting walls, and floors and trim and baseboards and cabinets will do great things for your biceps.
Bending over into a flower bed to remove weeds and dead flowers will work your butt till you scream as you sit down.
Running away from wasp nests and deer flies are great for cardio.
Sitting on an ant hill and having to hop up so quickly you almost pull a muscle is plyometrics, didn't you know?
And the tan and sunburns you get from being outside so much? Well they just add a wonderful summer glow to your kicking new body!
I'm being serious. Really. Three weeks off and I've lost about five pounds. I swear my arms are more toned and my butt lifted up a bit!