Origami Tessellations is the website of Metafilter member Eric Gjerde. In addition to the many interesting posts on the main page (such as this article about an artist who lasercut an 85:1 scale model of his house into a hardback book), the site features many original pieces by Gjerde, with downloadable PDF diagrams & graphics to show you how to make your own geometric art out of paper.
Moneygami is origami made from U.S. currency; the subtle genius lies in the way the artist incorporates the prints on the dollar bills into the facial characteristics of the finished figures. More moneygami here. Via.