We did a lot of driving this summer.  Our kids are pretty ok in the car.  We give each (who are old enough) of them a reuseable grocery bag.  In this goes a clipboard, washable coloring implements of their choice, a pad of drawing paper, a new book, and a stuffed animal of their choice.  I have a separate bag with blank paper, some paper games/printouts (such as Mad Libs, Travel Bingo, etc.), anything to entertain the baby, and all in car electronics.

We consciously did not purchase an in-vehicle DVD player when we got the new minivan with our 4th.  We figured on using individual electronics (most of which we already had and we expect to purchase more as they get older) and I didn’t want to be responsible for disputes as to what trips were long enough to qualify for DVD watching.

Since no child has their own, hand-held electronics currently get rotated through the vehicle.  For this summer we had an iPhone, a Kindle Fire, and a Nintendo DS among 4 kids.  None had internet connections.  The iPhone can be recharged in the car, but the others had to wait until we stopped for the night.  So, most devices had two available turns.  Between these options, plus the inevitable free meal toys we accumulate, the boys were fine for many full days in the car.