Drive a car in a carpark and also in a dream.
Use the 'W', 'A', 'S', and 'D' keys to move, and the mouse to move the camera.
Use 'Esc' to reset, 'Del' to quit, 'M' to toggle music, and 'L' to toggle the main light.
I prefer playing with the light and music off, but all versions are official dream cannon.
If your Unity 3D is up to date there's a new, free, beta version of the 'standard assets' in the Unity shop. Search for 'sample assets'. It includes car things.