The Boca Raton library has a new loan system for its best-sellers. They are charging $5 for a small set of really hot titles. It's good because most people don't need the new releases so fast, so they are happy to get other books for free. But if you REALLY want the new release, they are much more likely to be available (because the less passionate don't borrow them) and these folks are willing to pay. And it makes the library a little bit of extra cash at a time when they really need it.
This is a great example of using basic economics to improve the usability of a business model. I love it.
Not enough usability practitioners apply their expertise to improving business models.