Can anyone please tell me what I have here?

http://64.67.181.109/images/mysteryplant.jpg

My girlfriend brought this home from Home Depot for twenty bucks. It's
nearly 8 feet tall.
The conversation went something like this...

Me: "What's that?"
Her: "I thought it would look nice in the living room."
Me: "How do you take care of it?"
Her: "Ummm... I dunno. Water it?"

So my first step is to figure out what the heck it is.
My apologies if this is the wrong forum.
Any help is greatly appreciated!

-Dave