I've been playing around with unity and made this vehicle physics playground game thing. 

Download it here:
https://drive.google.com/open?id=0B_vuW-5XgUwZS20yWUVGYmVnVEE

Make sure to download the whole zip file. Here a hint:
http://i.imgur.com/eYYX7Xi.png

Controls:
awsd  or arrows keys to drive
r key to reset 
escape key to quit game