The Scratch programming environment is very popular with kids. Using the Arduino, we can introduce accelerometer control so your games can react to the tilting of the accelerometer.
I covered the basics in the instructable below:http://www.instructables.com/id/A-Gentle-Introduction-to-Arduino-for-Scratch-Users/
For people comfortable with Arduino and Python, I covered the use of an accelerometer to control a flight simulator in the following Instructable:http://www.instructables.com/id/Flight-Simulator-with-Arduino-and-Python/Let's Get Started
If you haven't done it already, follow the instructions on this linked page http://goo.gl/4pU2h
to download and install :
1. S4A ( Scratch 4 Arduino) and
2. the Firmware for Arduino to talk to S4A