[DML] My cooling fans stayed on...

Yesterday when I went to start my car, I heard a loud CLICK from the engine, and the cooling fans came on. The engine was completely cold. The key was only in the "on" position. Upon further inspection, I realized the click was coming from the alternator. It seemed like it wanted to engage even when the car was off. I then started the car and shut it back off to see if the alternator was just stuck or something. But nothing changed. I unplugged one of the connections to the otterstat switch, but the fans stayed on. The only way I could shut them off was to pull the jumper wire in the relay area. So, then I decided to drive the car anyway to see if it would fix itself. And, sure enough, it did. As soon as I pulled it out of the garage, the fans went off and all was back to normal.

My question is; what happened here? Is this a common occurance? Is this a symptom that something really bad is about to happen to my car? Anyone else have this happen to them? Thanks in advance for any help.