A girl I went out with had a ferret. It was pretty slick. A white female one named Tally. We let it loose in the apartment and sometimes it was annoying, nibbling away at my feet or messing around in the computer wires, but it was awesome. I had to look after it for a day, and it exhausted me to no end. Those things are totally hyper.
She walked it outside on a leash often when she went for small errands, it seemed to be having a blast then.