Ideas for car games for two teenagers on a four hour drive?

We're going to the beach...and we've got movies but is there anything else we could do?Ideas for car games for two teenagers on a four hour drive?
make a list of absolutely ridiculous objects ie... John Deere Tractor working a field, red barn, red roof, windmill, indiana license plate, on and on. No winners just plenty quality time spent together. We are old now but we still do it. Just not near as often. Don't forget a custom painted pick up, a milk tanker, or oil but usually milk, after the first hour ad a bumper sticker from home,Ideas for car games for two teenagers on a four hour drive?
If they need games and movies for just a 4 hour trip and cannot enjoy looking out the window, I just simply do not know what this world is coming to.