Motion Tracking and wireless networks (interactive gaming) - clueless

Firstly, I'm very (very) new to arduino, so please forgive any errors relating to terminology or technical details.

I'm an industrial design student, looking to integrate some interactive features into an upcoming product. I've wanted to start learning arduino for a while now and this seemed like the perfect opportunity. Conceptually I'm wanting to design a toy/game that gets kids to be more active. Here's what I need help with:

I want the kids to carry around an object, for example a "ball", that keeps track of their movement. This is not to say that the exact path they follow must be recorded, for all intents and purposes they can run around in a circle if they want, as long as they're moving. Instead i want to be able to convert their movement, ie the changing location of the ball, into "points", thus incentivising them to be active. I was hoping anyone had any suggestions for me? So far I've considered using a pedometer, inertial trackers, GPS etc.

Next, I need a way for the "ball" to communicate wirelessly with the other devices in the system. I want each child to wear a "watch" with an embedded RFID tag that is read by the "ball" (which will obviously require an RFID reader module) so that the system can assign the relative points to the user, or team, that is carrying it. The system (console) will randomly select who should be in possession of the ball and alert that user, via vibration/LEDs etc in their "watch", that it is his/her turn to carry the "ball". If they do not use the ball to scan their watch in a predetermined amount of time, they are penalised and the system will select a new user to carry the ball.

Finally, I need the "ball" to communicate with a main "console". When the balls are returned to the console, the points are essentially "transferred" to the console. The console determines a winner, based on the highest number of movement points "collected", and then displays who the winner is to the users.

Any help / input will be greatly appreciated. Thanks in advance.

Difficult project if you are just starting out. Start with the most difficult part first, which would be the motion tracking. Once that is solved work on the other parts.

As kat indicates, not a trivial project by any means. However, starting with the most
difficult part kind of goes against the idea of the learning curve, especially for someone
not well versed in electronics. I would start by learning to program the Arduino first.

For motion tracking, I would try a 2-axis or 3-axis accelerometer. Can be had for $30
or so, and would be fairly easy to imterface to the Arduino. You don;t need to track
the exact path of the kids, just get a good feel for their motion.