I regularly give a talk called ``Really Big Numbers''. During the talk we go from small big numbers (like the population of the earth and Avagadro's number) to pretty big numbers (like the number of atoms in the universe, googols and googolplexes) to really big numbers which are way, way too big to event write down in our universe.
Here's the first version of the talk from Melbourne uni's Science Festival in 2017.