A couple of year ago we were flying somewhere and at the back of the airline magazine there were instructions for making a peacock out of a dollar bill. It was a good way to spend the flight. I actually managed to make the peacock and I still have it. The thing I really liked about the instructions is that it showed the steps with a real dollar bill. There are plenty of landmarks on a dollar bill, so it made it easier than folding with a blank sheet of paper.
My dad bought me 2 dollar bill origami books for my birthday. On the flight to Denver last month I took one of the books--which came with practice play money---and tried to make an eagle and a double crane. Unfortunately the instructions do not show the steps with a real dollar bill, just with a green rectangle. Still, I was able to make the eagle. I wasn't as successful with the double crane. I just couldn't get one of the steps--so I ended up turning it into a camel! I'll have to keep practicing. Eventually I'd like to make the koi---it looks awesome, and really, really hard.