Doubling Pennies - I hate math except when it's cool like this...

I was listening to one of my favorite social media bloggers, Robert Scoble talk about face book here and he referenced ''doubling pennies'' I've heard him say this before, and I intuitively knew the answer, but not the 'why' behind the answer. So a quick google search yielded Dr. Math's simple and concise explanation of the ''Doubling Penny'' Kewl. Now to figure out a way to actually make that happen.