Now, put the player in your car. Then, reverse the cables on your car's battery

HA! I did this once on accident, long story short, tornado came thru, battery was dead in the truck for a fishing trip the early the next day, it was cold, my tux didn't come back from the cleaners, etc etc...
Anyways, it was one of the Optima batteries with the + and - molded into the top, hard to see at a glance at night with no flashlight. Besides I knew what I was doing. I didn't realize that they put the caps on the wrong posts (pos on neg, neg on pos) and didn't think much about how loose the negative was and how hard it was to get the positive cable on the post. Truck started, popping like popcorn I heard fuses go, the tachometer was going nuts bouncing all over the place. I figured it out pretty quick, and it was only 15 fuses, a grounded AC compressor and a fried Pioneer head unit... Amazing the battery didn't blow up... And it all works fine now. 5 year 70k mile warranty paid for itself there.
3 months of a boom box in the back seat until my empeg number came up in the queue!!!