This is a 2007 video, but it's still pretty cool.
Samuel Arbesman, in an effort to diagram and present our galaxy, the Milky Way galaxy in a way that non-scientists could grasp in terms of relationships and space, came up with a nifty graphic tool. He diagramed the Milky Way by using a convention Subway Transit map as a model. It's pretty cool; click here to read more. Click the image for a larger view with information about scale and the color-coding.
A star's habitable zone is the swath of space in which a habitable planet might exist. Earth obviously is square in the middle of Sol's habitable zone. Too far out and you're too cold to easily support life, like the icy Neptune. Too close in and you're molten hot, like Mercury.