An interesting point: To the best scientific guesses we have, the Universe .. Everything, ;-) .. shouldn't be more than a few Googol (10^100) kilometers wide, and it's probably a sphere or hypersphere. So you would use Pi to calculate its area or how much stuff is inside of it.

The thing is that to calculate anything to a Googol with significant digits, you only need 100 digits of Pi. So we could calculate the number of quarks (small atomic particles) in the entire Universe with, giving ourselves a thousand times more head-room than we think we need, 100,000 digits of Pi.

Here is the first 119,000 digits of Pi. Just imagine - with this number we could calculate perfectly the amount of atomic particles in Creation, if we had Its diameter (or some related precise measurement).

So, if this is the case, why do we have supercomputers working at this minute on Pi's digits well into the Billions? And why do people have it memorized to all those digits?