I've had enough of these sour experiences that I'm looking for a small cheap digital camera to get the license plate (I'll never remember the number).
Last weekend, a car accelerated from behind my wife, got in front of her and then hung a severe right hand turn. My wife had to come to a full stop to avoid getting creamed. 5'1" spitfire that she is, she chased down the car, abused the driver to no end and then came home and called the police.
Now we get to see whether the suburbo-cops will do anything.
(I'd b1tch about cars more, but I've had even more bad experiences with other cyclists riding beyond their abilities or out of control on local MUPs - when I want to go full out I do it on the road, not a MUP)