Explore other star systems' habitable zones -- and our own billions of years hence

The Circumstellar Habitable Zone Simulator provides detailed views of six star systems known to have exoplanets. You can change the stars' mass and the planetary distances and fool around with Goldilocks' breakfast, but it's the timeline control that's scary: drag it right to fly through the billions of years, watching the habitable zone head out of town as the star goes nova then contract to nothing.