Galaxy Zoo is an online project to classify the type of galaxies in large surveys. It was launched in 2007 to display objects from the Sloan Digital Sky Survey (SDSS) and prompt for input as to whether they appeared to be elliptical or spiral and the direction of the spirals. Tens of thousands of volunteers have classified millions of galaxies. Survey results have been published and interesting galaxies have been discovered and updates of the project have been initiated: Galaxy Zoo 2 (GZ2), and Galaxy Zoo: Hubble.
Galaxy Zoo 2 (GZ2)