All right, so I don't. Not at all. But I did try out a Tai Chi DVD as my exercise program yesterday (instead of the workout cards), and it turned out to be pretty good exercise. The slow movements make your muscles work more than you'd think.
It'll clearly take some work to be any good at it, though. About halfway through, I found myself with the wrong foot forward, trying to figure out exactly how it had happened. I thought I'd been following the instructions in the video, but there I was. Still, it was fun and relaxing and a pretty solid workout, so I'll be trying it again.