You're up late, banging away at your keyboard. You find the hole you were looking for. Now you just find the right directory, copy a couple files, back right out of the system, and erase your tracks. Within 15 minutes of finding a back door into the network, you've downloaded transaction data for all credit card transactions within the last two years. You'd think credit card processing companies would be more secure than that.
The FBI should be busting down your door any minute now. But they won't. You print out your keystroke logger info. You make a phone call. "I got in." They don't believe it. But when you deliver the keystroke log the next day, they're floored. They cut you a check, and offer you an even bigger contract to help them fix the hole.

Do things that should get you arrested - but get paid instead. Ethical Hacking is so cool.