Ophcrack is a free Windows password cracker based on rainbow tables. It is a very efficient implementation of rainbow tables done by the inventors of the method. It comes with a Graphical User Interface and runs on multiple platforms.
PWNtcha stands for "Pretend We’re Not a Turing Computer but a Human Antagonist", as well as PWN capTCHAs. This project’s goal is to demonstrate the inefficiency of many captcha implementations.