Comet Siding Spring (named after the observatory in Australia from where it was first spotted) is on track to have a close encounter with Mars in October 2014. Here’s what it’ll look like if you’re a Martian:
And here’s more info on Comet Siding Spring, in case you’re curious:
http://www.space.com/20443-mars-comet-2014-flyby-science.html?cmpid=520721