What is the biggest number anyone has named?

Numbers go on forever — you know that. But has anyone ever bothered to name a really, really big one? Not just count to a billion and stop for lunch, but actually invent a word for something so huge it makes your brain itch?
The answer is yes, and the story starts with a nine-year-old kid. In 1938, a mathematician named Edward Kasner asked his nephew Milton what you should call a 1 followed by a hundred zeros. Milton thought for a second and said, "A googol." Just like that — he made it up. One googol: 10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000.
