I should have seen this one coming: A device that plugs into your OBDII receptacle, communicates with either your iPhone or Droid, and reveals your cars innermost secrets. Even allows you to reset the "check engine" light.
Now you can call your mechanic, and he can see instantly what's wrong with your car and, since you have the same data, he's limited to offering to repair what's actually wrong.
Also the teenagers worst nightmare: If you take the car over 55mph, or hold the throttle to the floor for more than .15 mile, the car calls your folks and rats you out. Worse yet, add one of those key-fob cameras to the mix, and when you bring your date home, her daddy will be waiting on the porch for you, shotgun in hand.
While the first part sounds like a much-needed advancement to automotive technology, I can remember when the latter part would have been greeted with horror. Today, for some reason, it doesn't seem like all that bad an idea.