Every student should understand the ins and outs of credit cards and how easily people fall in the trap of interest payments. Students research their own credit cards, you act as the bank which approves a card, then the students pretend to max it out by buying a few "want" items. They create equations (or excel spreadsheets) to find how long it will take to pay off the debt. This project also goes into a few scenarios such as making a late payment or paying double the minimum required payment.
Every year I have done this project, I have students and parents thanking me for helping them understand credit cards a little more.
Included: 5 part project, peer-edit rubric, teacher grading rubric, and sample project for one part.