I have a treadmill but no time for it with the kids home and trying to work full time. I do short yoga videos, take the kids for long walks. A few times a week, we turn on music and all dance together.
Of course you can get a great workout from home. I have several DVDs, several of which I have found at thrift stores for $2 a piece. I have yoga equipment (blocks, mats, straps), dumbells, and resistance bands.
I do count running and walking outdoors as exercising at home or, perhaps better said, from home because it doesn't require a gym membership.
No matter where you workout, a training session is only as good as the effort you put into it, right? If you keep using the light weights and never increase, you'll never get stronger. If you don't push a little harder during your cardio sessions, why bother? And if you do the same routing over and over again and never mix it up, you'll never change.