Founded by Mark Zuckerberg, Facebook was designed as a social networking site for Harvard students. After spreading from Harvard through the university ranks and down into high school, Facebook was opened to the public in 2006.
Facebook is full of fun applications that you can add to your Facebook profile. Play games with your friends, battle each other, send gifts, create virtual pets or virtual gardens. There are just so many things you can do and so many options you can add that you'll never run out of fun things to do.