To play I Spy, a classic travel game, one person in the car will choose an object around them. He or she then gives the other people in the car a clue by saying: "I spy with my little eye, something…." He or she then will state the object's color, give the first letter of the name of the object or offer another clue.
Be sure that players don't choose an object that the car will whiz by too fast. Instead, go for something that is inside the car or that will be in everyone's line of vision for a few minutes. The person who guesses the object correctly is the next person to spy a new item.