SAHM to a 1 yo. I try to get out 4 or 5 days a week to the park and run/walk with him in the jogging stroller. I do between 4 and 7 miles each time. During the winter, last year, I put him in the bouncer while he watched me to an aerobics video. Now, it will probably be the playpen, or do it while he naps. Or I do the stair stepper. I also do leg lifts while lying in bed nursing. I have my hubby take over baby central for an hour some evenings while I run to Curves or a step aerobics class. Or go visit the folks and leave him with grandpa long enough to hit their local Curves.
But the easiest way to exercise...I park waaaaaaaay at the back of the lot, all out by my lonesome, then carry the baby in. At 23 1/2 pounds as of his Dr. appt. today...that's some hefty weight lifting.
Oh, and if you have stairs, I use the ones at my parents when I'm there, strap on some leg weights and see how many times you can run up and down them. Believe me, the kids will be looking at you wondering what you're doing. So you get exercise and entertain them at the same time. LOL