Always keep a disposable camera in the glove box of your car. This way, if you are in an accident, you can get pictures of the accident, the car placement, the people that were there, other cars, etc. This can really save your butt later when some "additional damage" magically appears on the other person's car.

Having the camera is also handy for those "I wish I had a camera" moments which always seem to pop up when you don't have a camera.

Make sure you replace the camera every year or so. The heat in the cat (during the summer) will degrade the film so that the camera does not last as long as it normally would