The Galaxy Zoo Supernovae hunt is closed down for a bit. Here's an update from their website:
"In the next day Supernova Zoo will be taken offline so that we can have a good look at the results from the past few days. Based upon your excellent feedback there will almost certainly be some tweaks to the classification interface and refinements to the decision tree. Supernova hunting is a very different challenge to galaxy classification and we’re delighted that our Zooites appear to equally adept at classifying galaxy morphologies as finding new supernovae!"