From site: The Mars Exploration Program is a science-driven program that seeks to understand whether Mars was, is, or can be, a habitable world. To find out, we need to understand how geologic, climatic, and other processes have worked to shape Mars and its environment over time, as well as how they interact today.
LearningReviews.com note: For kids, the site includes interactive games and activities in the Mars for Kids section. For teachers, there are classroom activities. Be sure to check out MarsQuest Online.