When withdrawing money from an ATM, the 'whirring' sound before your money pops out is actually a recording. The actual mechanism is so far back that you can't hear it.
According to some estimates, Americans are sitting on $30 billion worth of unredeemed gift cards.
A Native American tribe in South Dakota collects bottle caps left by campers, using them as currency. Several banks in the area now recognize the caps as legal tender.
One year, Elvis Presley paid 91% of his annual income to the IRS.