Nifty little system for a reasonable price. It has dual cameras that record the forward view and inside the vehicle (with IR illumination for nighttime), and interior audio. It also records GPS information, including speed.
The GPS/speed info can work for you, or against you, should you choose to introduce the recording in court proceedings. The audio recording legalities are an ongoing issue in NH.
http://www.spytechs.com/Car-Cameras/dual-view-cam.htm (http://www.spytechs.com/Car-Cameras/dual-view-cam.htm)
cool
I had a window sticker idea to add to people's "I do not consent to a search"
"Attention highway robber, driver carries less than $100 and will not pay fines if convicted."