Scavenger Hunt
Make a scavenger hunt for kids that will keep them busy checking off items they see out the windows. Offer a small prize to the kid that marks all the items off first. Consider what kind of areas you'll be driving through and tailor the scavenger hunt accordingly. If you're driving through the country, put items such as farm animals, tractors and barns on the hunt. For city driving, have items such as tall buildings, taxi cabs or stop lights. You can include people such as police officers, and even familiar landmarks such as restaurants or retailers. Make the hunt simpler for small children and draw a little photo next to the item so they know what to look for.
Alphabet Game
Beginning with the letter "A," each child must take turns naming things they see outside the window that begin with that letter. Once they have spotted three items and named them, it's time for the next person's turn. The next person can either choose what letter they want to use or continue in alphabetical order.
License Plate Fun
Try to make words or phrases from license plates you see. Some of these can be pretty silly and this game can be a lot of fun. The phrase doesn't have to make sense, just see what you can come up with based on the letters on the license plate. If one says "CEF," for example, you can say something silly like "Cats eat flies." The funnier, the better.
Magnet Words
Make magnet letters or parts of words using magnet sheets and your computer printer or label maker. Create lots of suffixes and prefixes that are simple but can be used to make many different words. Or, you could make interesting words that can be put together to make silly sentences. Give kids a metal lunchbox they can use to stick the words on to arrange them. See who can make up the funniest sentences and words with the magnetic letters.