This system uses 4 controllers which send signals to a central hub which holds an Arduino.
It was designed for use with a game called Fraction Smash that my group was developing for a class. Students would enter a fraction using the keypad to re-size their character and then hit the smash button to break through the door if they are the right size.
More info here:
http://pdi-studio5.wp.rpi.edu/fraction-smash/
Step 1: Cut out pieces
The .DXF files are attached for automated processes.
All of the CAD files and assemblies can be found here:
http://pdi-studio5.wp.rpi.edu/files/2011/12/Fraction-Smash-CAD.zip
Step 2: Add wires to ethernet keystones
This system uses Ethernet cables for the controllers to communicate with the hub. I used three wires on the Ethernet cable, power, ground, and data, although there is space for up to 8 wires if you need more room.
Keystones are easy to use. Simply place one wire in each slot and then push the plastic cap down on top. It may be too hard to do by hand so I used a pair of pliers to push it down. It is not necessary to strip the wire as the keystone will cut through the insulation for you to make a connection.
Keypad (3.95)
http://www.sparkfun.com/products/8653
Buttons (1.49)
http://compare.ebay.com/like/120554574811?var=lv
Ethernet Keystones (1.24)
http://www.monoprice.com/products/product.asp?c_id=105&cp_id=10513&cs_id=1051308&p_id=5371&seq=1&format=2
Arduino (29.99)
http://arduino.cc/en/Main/Buy
Breadboard (5.95)
http://www.sparkfun.com/products/137
Wire
Ethernet cables
Super Glue
For more detail: Game Controllers using Arduino