At random intervals, the instrument panel will do one of several things: the speedometer will fluctuate wildly, even while sitting still, the ABS and other warning lights will flash, the anti-theft light will stay on, or all of the above. The car will usually, but not always, shut off. So far I have always been able to restart it.
It happens whether the car is hot or cold, whether the car is idle or moving, whether in park or drive.
It happens whether the A/C is on or off.