Who will you be riding in the car with? Any siblings close to your age?
A fun game that we like to play is, uh, I think it's called the ABC game...anyway, you start out saying, "I'm going to Disney World, and I'm bringing..." and say something that starts w/ the letter A (it doesn't have to be something you're actually bringing). Then the next person says, "I'm going to Disney World, and I'm bringing...[whatever the A word was] and [something starting w/ a B]. You keep going like that. Eventually people will not be able to remember all of them; once that happens you are out of the game. Then you keep going til only one person is left, the winner! It's pretty fun, especially when you think up goofy things, like a toothpick or something. 20 Questions is also a fun game to play on the road.
I also enjoy reading, or writing in my journal about the sights we are passing or any interesting things that happen on the trip.
Have a great time!!!