How do you get the moon with a single piece of paper? Fold it in half a mere 40 times, that's how.
This short video from TEDeducation has to be the greatest illustration of exponential growth since Louis Pasteur demonstrated fermentation and germ theory, subsequently bringing about the cures for rabies and anthrax. (Yes that's a big call, but watch the vid.)
The maths is startling. After 10 folds a piece of paper is only as thick of the width of your hand. 10 folds later and you're 440 metres high wondering what the fuck you're doing. Twenty more and you've reached old moony.
Pretty mind-blowing - but why stop at 40? After 100 folds you'll be at the radius of the known universe. One fold for man, one giant fold for mankind.