googazillion 

The number 1 with a googazillion zeros after it. An unquantifiably large number.

She has a googazillion pairs of shoes.

googazillion by sandiegoecho September 25, 2009

gigazillion 

a billion gazillions

"What brilliant economy of explanatory causes, compared with all those gigazillions of independent electrons all just happening to be the same!" - Richard Dawkins, "The God Delusion"

gigazillion by Adam Henderson December 14, 2008

googillion 

A googillion is an astronomer’s "largest number possible" synonym for everyday real-world objects that are unknown and unknowable. Example, from string theory, how many strings are there in the universe? The answer is a googillion. Although the real answer is a specific number at any given point in time, the number is both an unknown and unknowable largest number.
Since any largest number can become larger simply by adding the number one, all the strings in the universe plus one is also a googillion.
source: Wikipedia, the free encyclopedia, Large numbers

Example, from string theory, how many strings are there in the universe? The answer is a googillion. Although the real answer is a specific number at any given point in time, the number is both an unknown and unknowable largest number.

googillion by steve byrne November 18, 2005