The Alphabet Game
Whether you've got teens or toddlers, the alphabet game is a good way to interact with kids on long road trips. You can play as one team together, or separate into two or more teams. You must find each letter of the alphabet at the beginning of a word, in alphabetical order, and you have to use road and building signs for your material. So if you pass by Zenbu Sushi while you're still on letter C, you can't count it for later! You must start with A, so "All You Can Eat," on a sign would be a perfect answer for letter A. Feel free to change up the rules a bit to suit your players and your drive.
Do you have kids who love sports? Are they all into the same books or movies? Trivia games in the car can be really fun if you have a few categories to choose from. You can make it really fun with different-sounding buzzers, noisy toys, or iPhone sounds for each player, or have them raise their hand first to guess (you might need a volunteer to officiate). Start with easy trivia questions like: Who is the President of the United States? Or silly ones: What did we recently add to our kitchen decor? And get more detailed as the kids get more interested.
There are two roles in this game: the guesser and the answerer. The answerer starts by choosing a person, place, or thing and stating, "I am a (person/place/thing)." The guessers then have a total of 20 chances to ask yes-or-no questions such as "Are you alive?" or "Are you located in Europe?" The questions become more and more specific as the guessers narrow down the options. This can be made a fun learning game as well by incorporating school topics like being a cumulus cloud!
If you have never played I Spy, you've missed out! This is one of the simplest car games of all time, and it's perfect for young kids. Start with something like a color, "I spy with my little eye, something...blue," and have your kids make guesses. Choose things that won't change much over the 5 or so minutes they'll be guessing. Specific cars are good, as well as grass, the sun, the sky, and even common road and highway signs. You can also choose things in the car like someone's yellow jacket or an iPod.