Here are some ideas to do on long car trips:

Draw

Listen to the radio.

Organize your glove box or center console.

Get a good debate going

Enjoy the silence and go to sleep.

Give disposable cameras to people and have a picture contest. The most interesting picture wins!

Play the car color game. Before you set off on your trip, have each child choose a different car color. Hand each child a piece of paper and pencil so they record a point for each time he or she spots a car with their chosen color. You could also use m&m's to tally points.

And a classic that never fails: see how many different states you can find on license plates.