Interesting idea about guestimating scale of things. One that I've always found interesting is how many different possible orders you can get with a deck of cards. 52! is a ridiculously big number
It's funny you mention this, I plan to add a more abstract "chapter" on probabilities and big numbers, not related to objects scales like the current game : chances to throw 5 dices doing only sixes, chances to die from a shark, chances to win the lottery...
