Your next question is, "Why would we want to go to Mars?", well humans are a very curious sort and it's part of the human condition. Humans have been explorers for eons and going to Mars satisfies that "what is over the horizon" itch. I also think it extremely important that we as a nation develop and use our own equipment instead of relying on someone else to take us places, I don't rely on my neighbors to cart me around so why should NASA.
I am highly in favor of private industry getting into the Space Exploration business as it will boost our employment and economy as well as taking some the tax burden off the US citizens.
I find it refreshing that we can discuss subjects like this rather than politics which is endless.