This article, 52 Factorial, has to be the most creative explanation of immense numbers that I have ever seen. The number of possible combinations of cards in a typical 52 card deck is:
And you would think that is unimaginably large. But amazingly, this article gives you a way to visualize it.
So what number is unimaginably large? The odds against every moment of your life being at all, let alone being what it was.