Usually there are no ways of letting other drivers know what you think of them other than the one-fingered salute or slamming on the brakes, but the brilliantly named Driv-e-mocion aims to allow you to be a bit more expressive. A small electronic display sticks on your back window, which you control from the driver's seat, displaying smiley faces or frowns as well as short messages like "thanks" and "back off." That's right, someone can cut you off and you can retaliate by giving them the ol' frowny face. Actually, since it's in the back, you'd need to get around them and cut them off for them to see it. Also, I'm not sure if flashing "back off" at someone riding your tail is supposed to make them sympathize with you or simply become enraged and tailgate you with even more fervor. Perhaps you're a risk taker. If so, you can pick up the traffic Driv-e-mocion online now for about $20.