I've posted before about Galaxy Zoo, and see also Phil Plait's posts introducting the zoo, oncounterintuitive results and what do to if you find something weird. They had a pretty cool collective result recently, discovering tiny galaxies that are rapidly forming stars, that they call "green pea galaxies" (which is apparently a different sort of beast from the non-galaxy I called a green crayon in my initial post) -- see here for more or here for the paper itself. Anyways, Galaxy Zoo has just announced a new project, the supernova zoo.