Wii Nunchuck is Wii remote controller with 3-axis accelerometer, joystick and two button combo. Those who have watched old Bruce Lee movies know how dangerous such Nunchaku could be in some hands 
http://www.youtube.com/watch?v=bRyDcB7qQFo
Olimex offers Wii-Nunchuck with UEXT adapter board for EUR 6.95 https://www.olimex.com/Products/Modules/Sensors/MOD-WII/MOD-Wii-UEXT-NUNCHUCK/
and now with RPI-UEXT https://www.olimex.com/Products/Modules/Adapters/RPi-UEXT/ you can connect Wii remote to your Raspberry pi
The Python code is on GitHub https://github.com/OLIMEX/raspberrypi when you start it you will see on the console:
the joystick coordinates, accelerometer XYZ values and two button status
Very nice, but what’s the purpose?
having joystick and play games with it?
Allows you to use the Nunchuk in your own programs. A very useful interface routine!
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