Comet Holmes is back in the news. If you don't recall, that's the comet that suddenly, and unexpectedly, outgassed a cloud of material in October 2007. It quickly became visible to the naked eye, even from large cities. Before fading, the visible cloud grew to larger than the Sun, and in our night sky was half the size of the full moon.
Here's a shot I took of the comet from right in the middle of downtown Covington on October 29th, 2007. I captured the image with a Canon DLSR attached by a t-mount to a small telescope: