While growing up almost all of us have tried folding a paper more than 7 times and failed but for Britney Gallivan. She derived empirical formula for approximate width needed to fold a paper in alternate directions and another one for approximate length needed to fold a paper in one direction. She demonstrated that a 1.2 km long toilet paper can be folded 12 times.
Here's the complete story and more.
An awesome quote by Juan Ramon Jimenez (in the article too)
"If they give you ruled paper, write the other way."