I highly recommend that you skip this game completely. The minigames are not fun, the game is buggy and it is saddled with a very poor menu design and interface.
Motion Sports is made up of several different sports: soccer, football, hang-gliding, boxing, horseback-riding and skiing. Each sport has several different game modes, which are unlocked by playing through the beginning modes. The game does not make it very clear how to unlock the other games. Just keep playing and eventually they'll unlock.
The sports vary in degree of frustration from boring to maddening. Here is my synopsis of each sport:
Hang-gliding: BORING. Put your hands at shoulder level and sway your shoulders back and fourth, up and down to maneuver the glider. Very little movement is required to control this exceptionally boring mini-game.
Boxing: FRUSTRATING. Most punches are not registered by the Kinect so you end up flailing your arms wildly hoping for the Kinect to pick up the movement.
Horseback Riding: YAWN. This game is boring, repetitive and not fun at all.
Skiing: CROUCH AND LEAN. If you enjoy crouching in a skiing position for minutes at a time you will love this mode. Crouch down and lean back and forth to control the skier. Combine the cramp-inducing crouching and the imprecise, broken controls of this game to produce a horrible gaming experience.
Soccer: MADDENING. Several different mini-games are included. The penalty shoot-out is probably the finest single mini-game; the Kinect reflects your movements as goalie accurately. The shootout mode is fun for a few plays but after a while is very repetitive. The other modes (target shooting, midfield shooting) suffer from very poor motion recognition by the Kinect. Attempting to precisely aim for the top corner of the goal is nigh-impossible with the unpredictable Kinect response to your movement - sometimes you kick way over the goal, sometimes low and weak.
Football: BROKEN. The running back minigames are boring and imprecise. Once again, the game suffers from inaccurate registering of your movements. When you perform well at the running back game, it's more luck than skill. The quarterback game is totally broken and unusable.
I found several other bugs in my couple of hours with the game:
1. The game freezing and locking up. I had to power down my xbox to recover
2. The game failing to recognize me numerous times even after playing dozens of games. This caused me to have to sign in to Xboxlive over and over again. I have not had this problem with any other Kinect games.
3. The "camera" inside the game moving far away from the action, rendering that specific game unplayable
This game is also plagued by a terrible menu system and is lacking in basic functions such as a "back" button. Avoid at all costs!