A million digits of Pi on one piece of paper (1.05 miles).
More about how and why: http://youtu.be/99Welatppzk
More Pi videos from Numberphile: http://bit.ly/PiPlaylist
As they unroll the million digits of Pi they point out facts such as the record point of memorization. There is another point where there is no #4 in a stretch of 157 digits. They'll also reveal, if you watch long enough ... the digit that is most common in a million digits of Pi.