I recently started my training program in Nike+ Kinect Training, and this game is kicking my rear end! I've tried many at home workout programs, but I found this one to be the most fun and challenging of them all.

When you load up the game, it gives you a quick introduction video hosted by two trainers. After they explain how the game/workout program works, you get to choose which one you want to be as your personal trainer.
After the selection, you start your first assessment test. This test gives the trainer information on your current fitness level, and how the program will be tailored to you. It asks you a few questions, asks you to do about 15 different exercises, and then gives you a score.
After you catch your breath from the rigorous test, you get to select which days you want to exercise. The game suggests that you do at least 3 days a week, but you can pick up to 7 if you want. You select which days work best for you, and the trainer will schedule workouts for those days on the calendar that you can see. The calendar is helpful to know what you've done, and what is coming up in the future. It also tells you how long the workouts will be, so that you can play your life around it.
The game itself is very informative. For the workouts, the trainer will show you how it's done first, and then you do it. The Kinect device is accurate in seeing you and knowing if you are doing the workout correctly. If you're form is off, the trainer will let you know to correct it.
Overall, if you're looking for a fun game to really burn the calories, this is for you. I was skeptic when I bought it because I played other active Kinect games like Dance Central and Zumba, and I found them to be very inaccurate and non-responsive to the kinect. This game will not disappoint!