I found an interesting idea over at KuddleKids.com. (The formatting of the site is wonky in my browser, making it difficult to read, but there are some good ideas there.)
The idea that caught my attention most was the "I Owe You...".

Every parent has times when kids seem to deliberately ignore your requests. They'll 'forget' to take out the trash, even though they've been reminded three times that hour, or they'll once again interrupt in the middle of a conversation- for the fourth time in five minutes.

KuddleKids suggests when you're dealing with that repetitive deliberate misbehavior that you pull out your sticky notepad and write "I owe you a NO!"
Date it, put a brief explanation, and the child's name on it. Then when they ask if they can go to a friends house, watch an extra movie, or have a second cookie, you pull out your sticky note and say, "Oh, looks like I owe you a "NO". Sorry."

This works best for minor stuff, and with a child who is not intent on lots of overt disobedience.

A positive twist on this tactic is to also notice when kids are making good choices: straightening up without being told, obeying cheerfully, or being kind to a sibling. Then you can present them with a sticky note that says, "I owe you a YES."

Compliment the good behavior in the presence of other children in the family, and you may suddenly find yourself surrounded by kids eager to earn a 'yes'. Obviously parents should be allowed to still make the final decision. But there are plenty of moments in parenting where an extra cookie or a play date with a friend or an extra half hour of reading time before bed will not make a bit of difference-- except to the child who is delighted by the extra privilege and the knowledge that he or she earned it with good behavior.