The ‘Guess what I am‘ Game can really be played anywhere, but being trapped in a car, makes this a classic.

The rules are simple:

One person states they are either a person, place or thing and the others then ask questions (are you blue, can you speak, do you bark, can you be eaten, etc) until they guess what the person is, upon doing so, then they are next.

To make it more challenging:

Riding in the car, and you are bored? try the ABC game:

The object is simple; to complete the alphabet first.  As you see  letters on billboards & other cars’ license plates you shout out your letter and point.  Once a letter has been claimed other players cannot use the same letter.  Make it harder by limiting to only license plates only.