What Does "Hell" Really Mean?

When it comes to theology, and my take on the Bible, hell is something I can't claim to have any kind of grasp on. I've read lots of different opinions, and know many different doctrines, and yet have no clue where I stand.

Jenny is in the midst of reading one of those books on hell, so we've briefly talked with each other about how much we'd enjoy having a conversation about hell with other people. We however, know that we won't agree with the mainstream version of hell right off, and that might scare many of the people we would want to talk with.

So here I am, asking all of your opinions. What is hell? Where is hell? How long is hell? Are people in hell now? Who rules in hell? Where did your beliefs of hell come from?