When have you hacked something to your advantage?

In Paul Graham's essay "What We Look For in Founders," he mentions that one of the five characteristics that he looks for is "naughtiness" - a quality of being willing to break the rules to get something done.

The question they ask applicants to explore this is "When have you hacked something to your advantage? Hacked in the sense of beating the system, not breaking into computers."

This is one of the smartest application or interview questions I've seen - it is tough to game. You don't want someone who cheats or breaks the law, obviously. But you also don't want someone who can't think or talk her way around bureaucratic obstacles in the service of a higher goal.