[ Movies ] Open Question : What is the Paranormal Activity series' plot?

I want to know because this cute girl that I sorta like has pretty much been talking and talking and talking about it all the time and I wanted to know what it's about. I want to watch it and all, but they don't have it on Netflix and I'm not gonna buy a DVD for it. I know what most of you are going to say, "Don't try to be something you're not," or "You don't have to be like hey," I'm just gonna go for it.

Source: http://answers.yahoo.com/question/index?qid=20130227175755AAqP41A

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