Explore the Galaxy Zoo! The Galaxy Zoo is a project that is using crowd sourcing to classify galaxies. Astronomers have a scheme for classifying galaxies based on their morphology that is old and not the most rigorous process, but by getting multiple classifications statistically significant facts can be drawn about each galaxy and the entire data set.
So all you have to do is go look at galaxies like the ones below and click on whether each is a spiral or elliptical galaxy. Go. Do it. Now.
JMP 57, 12: quantum mechanics for the universe
6 hours ago in Doc Madhattan