Toilet Paper Origami
Have you ever noticed that in hotel rooms, the cleaning staff will fold the end of the toilet paper roll into a little triangle? It's one of the last things they do when cleaning a room...it's like leaving a mint on the pillow, to show that the room is clean and ready for the next guest.
Thirty or forty years ago, no one did this. Then the idea caught on, and spread, and now hotels all over the world do this. Some have even moved on to fancier designs, such as this elaborate fan:
This picture is from Linda Wright's book, Toilet Paper Origami. Yes. There is such a thing as toilet paper origami. Some websites such as the Origami Resource Center provide tutorials on how to fold flowers and butterflies into that last sheet on your roll.