This is the T-less Bill switch!
One of the best tricks in magic is probably the changing bill. Let's say you are at a party, showing a trick or two. Then someone asks if you can change his 5 dollar bill into a 10 dollar bill -NO PROBLEM!!
Take the bill, show it around, and slowly fold it up. Then all of a sudden, the bill seems to be changed into another value! Unfold the bill again and indeed it changed into another value! Show this bill all around and if you want hand it out for examination.
Ron Timmer's version is called the T-less bill switch -It is not using a "classic" magic prop and the magic and handling are extremely clean!
You can use this switch for any bills; Dollar, Euro, Pound, Yen, you name it.