If you haven't already read Paul Heckert's article explaining why Mars will never look as large as our moon in the sky, please enlighten yourself.
E-mails describing either Mars as large as our moon or two full moons appear in Earth's sky at the same time have been circulating for a number of years now. Just five minutes ago I got yet another e-mail filling me in on this once-in-a-lifetime not-to-be-missed opportunity. While I certainly appreciate that they wanted to share an exciting astronomical event with me, I just wish that it was something that is actually going to happen. Their intentions are always good.
The problem with these e-mails is that it tries to "super-size" the science of astronomy. With a little background and insight into the subject, astronomy doesn't need outlandish claims to be attractive or powerful, it is already. Astronomy entails everything in the universe from the beginning to the end, or a continuous loop, if you prefer. It contains the largest objects possible (the cosmos) and the smallest (from atoms to the seed of a black hole).
If you want to watch something great in the night sky, there is something every month. And on the date currently given for the great "two moon" event, August 27, there is a great event within hours of this - when the moon dips into Earth's shadow in a total lunar eclipse.
So if you get an e-mail proclaiming Mars will be as large as the moon, it is okay to get excited about it. But do a little research first to validate the claim and then when you realize it's not true, forward on a different e-mail, about the upcoming total lunar eclipse or tracking the International Space Station or space shuttle soaring across the sky as they are currently doing. We astronomers really do appreciate your enthusiasm, we just want you to have something real to get excited about.