Poltergeist?

After discovering an open window in my basement yesterday (which couldn't have blown open, as it slids open sideways, nice thought tho), a couple other weird things happened. Ashley and I pulled into the garage after running some errands and heard music. The stereo that sits on a shelf in there was playing. Baffled, I went over and turned it off. Still wracking my brain trying to figure out the window thing, now I'm wondering how the stereo got turned on. Then while watching the news at 10:00, the electricity went out! The dog started scratching at the basement door, so I let her up, I hunted down a flashlight and the girls ended up down in my room. We waited for awhilel for the electricity to come back on, but I finally got too tired. Luckily there are cell phones and the girls found out the electricity was out in other parts of our town, not just our place or cul-de-sac, so I felt a little better about that. But I had 2 teenage girls sleep with me, along with Chester (lucky I have a king size bed), and the two big dogs slept on my floor. Ashley thinks it's poltergeist. I think it was just a weird twist of events!