Google’s name is an alternative spelling of “googol” which is equal to 10 to the 100th or 10¹⁰⁰. That would would be a 1 with one hundred zeros behind it. I always though that it may have been something that one of the founds thought of after experiencing some sort of brain trauma. I learned this while reading The Anatomy of a Large-Scale Hypertextual Web Search Engine. This is the doctorate thesis of Sergey Brin and Lawrence Page (the founders of Google.) In it they state:

We chose our system name, Google, because it is a common spelling of googol, or 10¹⁰⁰ and fits well with our goal of building very large-scale search engines.