Paper money is not just for spending -- it is also great for origami.
The Asahi website has posted a story about "Turban Noguchi," a popular origami made using a 1000-yen bill. The bill features a portrait of Hideyo Noguchi, the noted physician and bacteriologist who, among other things, discovered the agent of syphilis in 1911. By folding the money, you can outfit Noguchi with a turban or other fancy headgear.
Asahi credits a Mr. Nakajima, a 29-year-old Nagoya resident, with inventing the original Turban Noguchi origami technique. According to the article, Nakajima discovered Turban Noguchi by accident one night when playing around with his money. "I was shocked by Noguchi's bizarre appearance," he says.
Since then, he has compiled a number of variations, some of which are featured on the Turban Noguchi no Sekai ("The World of Turban Noguchi") website. A couple of links to instructional YouTube videos also appear on the site. This video, for example, shows how to fold a standard Turban Noguchi, and this video shows how to make wedding rings from a 1,000-yen bill and a 5,000-yen bill. Nakajima offers a word of warning to overzealous origami enthusiasts, though -- too much folding can destroy the money, so be careful.
Another website, called Turban Noguchi to Yukai na Nakama-tachi ("Turban Noguchi and His Delightful Companions"), features an AMAZING gallery of origami made with paper money. Highly recommended.