I had previously written a post about the ISON comet, anticipated to be one of the brightest comets in the past several hundred years. Scientific American now has an article about it, noting:
After it loops around the Sun and forms this tail, the comet should then pass relatively close to Earth—not near enough to cause any worry, but close enough to put on a great show. Viewers in the Northern Hemisphere will get the best view as the comet blooms in the weeks approaching Christmas 2013. The comet could grow as bright as the full moon.