This is a interesting application that uses a wireless “dongle” to plug into all modern cars diagnostic port, and it lets you read out all kinds on interesting information (in real time):
Rev Features
Built-in Metrics (No special hardware required)
Lateral and Forward Acceleration: Graph your cornering, braking and acceleration G-forces. (Available in Rev Lite)
GPS Track: Visual track displays your location and acceleration data – see how you are braking and accelerating around corners. (Available in Rev Lite)
OBD Metrics (Requires OBD-II/WLAN interface hardware)Vehicle Speed
RPM
Fuel Consumption
Engine Coolant Temp
Fuel Pressure
Calculated Engine Load
Throttle Position
Intake Manifold Pressure
Air Intake Temp
Timing Advance
Mass Air Flow
Fuel Level
Barometric Pressure
EVAP System Vapor Pressure
Fuel Trim[From Rev]
Views from the recreation ground. 
