At Galaxy Zoo, hundreds of thousands galaxies in Hubble Space Telescope images need classifying. Astronomers need these classifications to help solve the puzzle of how galaxies form and evolve. People wanting to participate are run through a simple tutorial. After completing the tutorial they are given new images of galaxies to classify.
The Galaxy Zoo Supernovae project involves looking at images of galaxies where bright spots have recent appeared. Supernovae are exploding stars and there are different types of supernovae. Participants then compare the bright spots with older reference images to see if these spots are indeed supernovae. Like Galaxy Zoo, a simple and brief tutorial is completed before they are set loose on new images.
If you love astronomy or just want to be a part of professional astronomy research, check these sites out.