Many goal trackers encourage you to jot down the things you want to do and encourage you to do them, but Go Fucking Do It is a little different. It will track your goals — single achievable tasks — and if you fail, give up, or find another reason not to, it will charge you money — a penalty you decide.
Some of the examples on the site are things like "I'll surprise my girlfriend every day or pay $100," or "I'll organise my life or pay $50," but you can apply it to anything you want to do, from writing a book to cleaning out a storage unit. Keep in mind that the best goals are single, attainable things as opposed to vague, sweeping statements.
Once you specify a goal, you set a deadline for it. Then you tell the service how much money is on the line, and enter a "supervisor" — the person that the service will ask if you succeeded at your goal. Once the deadline passes, your "supervisor" gets an email. If they say you completed your goal, everything's fine. If you miss it, you get charged the amount you put on the line (via your credit card).
If you approach the idea honestly, it could encourage you to put your money where your goals are. As for where the money goes? Well — it goes to the founders of the site — which in itself is supposed to be incentive to hit your goals. They even note that if the money went to charity, or even the "supervisor" friend, it would decrease the pain threshold. Losing the money is something you're supposed to not want to do under any circumstances, so giving it to a friend or a charity — things perceived as good things — create a disincentive to hitting your goal. You can read more about the developer's thought process behind Go Fucking Do It at his blog here, and there's a pretty good debate over the tool that's been simmering at Hacker News for a few days at the link below.