I sit on a shelf or a box or whatever is nearby and they sit on my feet. This works my calves because I have to keep my feet flexed so they don't fall off. And then I swing back and forth, like the weight lifting machine at the gym! It's great!
The problem is, I can't make them stop. They just want to go on forever, and it burns! I can't keep that up for more than a couple minutes at a time. Silly children, let's switch places and then you can tell me how long you can go for!
But hey, I'm trying to be healthier. Once I get back to school and I'm walking a whole bunch, I think I'll be loads better :)