Quaker
Growing up, my dad would play Quaker with us when we went on long car rides. It went something like this:

Dad: Hey let's play Quaker. This is how you play, we all try to see who can go the longest without talking.
Us: Ok, that sounds fun
Dad: Ready, Set, Quaker

Silence............. {followed by us pinching each other trying to get the others to talk =0).}

Today I introduced this game to my girls. It worked like magic. Gwen even played along, and we had a nearly silent ride home from our meal. Afterwards, Liv told me how fun it was to play Quaker, and I agreed =0).