Galaxy Zoo – Supernovae was a project that launched in August 2009 and was designed to let volunteers help astronomers at the Palomar Transient Factory hunt for massive, exploding stars (supernovae) in their data from the Samuel Oschin Telescope in Southern California. The project was an outstanding success, with Zooniverse volunteers discovering hundreds of supernovae that would otherwise have been missed. These fantastic efforts lead to many scientific publications and major advances in the automatic detection of such events.

Read more about it in this blog post by the project lead, Mark Sullivan – http://blog.galaxyzoo.org/2012/08/03/supernova-project-retires/