The thing is, it didn't feel like I even did anything! Ten reps each of some strengthening exercises, two cardio drills and as much yoga as I could do (you have to unlock a lot of things in the game before you have access to an entire workout). When I finished, I even thought it had been too easy, that I wasn't going to get as much out of this as I thought. Clearly, I was wrong. Apparently the whole stress on balance and center of gravity and core strength worked my body in ways I was not only unused to, but completely unprepared for.
Final review: If you, like me, have little time and money to get to a gym, I highly, highly recommend Wii Fit--just don't go into it all naive like I did, lest you not be able to move the next day.