Just like every day isn't.
I've already debunked this story a zillion times -- every year, it seems, including 2007 -- but I'll put up a reminder now since today is(n't) the day. The story is still around; a friend asked me the other day if there would be "two moons in the sky", and I think this is what she meant. I also did an interview for this for the Orlando Sentinel. If you see more articles on it, link to 'em in the comments! Another example: Emily.
1) Mars is not as big as the Moon in the sky.
2) Mars can never be as big as the Moon in the sky.
3) You need a decent telescope to even see Mars as a disk instead of little orangey ball of light.
4) If Mars looked as big as the Moon, we'd be in for a whole peck of trouble.
5) Mars isn't even close to the Earth in its orbit right now. We're approaching it, like a car on the inside track at a raceway, but it'll be December until we're at our closest. Even then, it'll be tens of millions of miles away.
6) Conclusion: go outside if you want, and enjoy the night sky. Jupiter is nice. But Mars is still a long way off and not much to see.
See you next year. Sigh.