Fairly recently (in the US), I had a very fake feeling dollar bill that I got as change. I figured it had to be real, since who would counterfeit a dollar? I tried using it in several self-pay machines at grocery stores and it always spit it back. I passed it on as a tip I think. I should have entered it into "Where's George" instead.
Isle, thanks for the website. This is good info (plus buying one of those marker pens that test bills would be a good investment.