Arduino Compatible development board with onboard CAN Bus interface, 3amp power supply, and connectors for displays or sensors. All while keeping the UNO_R3 footprint so other UNO compatible shields will work.
Download the "CrumpCanbus" folder and place it in your libraries folder. it is a modified version on sk pang's canbus code for their shield that can be found here: http://skpang.co.uk/catalog/arduino-canbus-shield-with-usd-card-holder-p-706.html
Examples are using the above libraries that use ODB-II PID codes to make requests on the CAN bus then display them.