Question: There comes a time when time-outs don't cut it anymore.

Normally, when my kids exercise poor judgement, I let them experience natural consequences. However, sometimes their actions go against what we are teaching them and the consequences are rewarding. 

When pre-teens break the rules or disobey, what consequences are appropriate?

Answer: 
It depends on the privileges they have. Sometimes, giving them extra chores is appropriate (say, if they've broken something and you want them to make restitution.) Many times, though, you'll want to take something away from them. Anything short of food, clothing, and the roof over their heads is fair game-- depending on the severity of their rule breaking.

Items:

* Cell phone
* computer
* TV
* games

Privleges:

* Playing with friends
* Being driven places
* Getting allowance

My dad always used to ask us the trick question: "What punishment do *you* think you deserve?" You can try that one if you run out of ideas ;)
Developmentally, preteens and teens are at the age they are supposed to question everything. This makes for some delightful challenges. The piece that helps with their questioning is that they also like to feel like they have some ownership or control over their life. It is absolutely appropriate at that age to sit down with your children and review the family rules and discuss them - find out what your children think of the rules - are there any they think should be added, amended or deleted. Ask them to justify any changes they are proposing and afford them the same. The more you involve children in these age groups with decisions, and explain the though behind them, the better decision makers they will be when you are not standing next to them. Additionally, ask them to help establish consequences. Depending on your child's personality, writing these out and posting them may have a great power for avoiding consequences. 

It is additionally important to have behaviors that will earn rewards and discuss those along with what the rewards will be. Most tweens are still very interested in pleasing adults and if they know that sweeping the kitchen floor will earn them a reward (thereby letting them know it has pleased you) they are more likely to complete the task. 

I do recall the "worst" punishment from my parents at that age was having a discussion about my bad decision, what was so bad about it, how I was going to rectify it and what I was going to do in the future - they were agonizing talks at the time, but they taught me how to think about results of decisions I make, eventually I was able to foresee the discussion and therefore avoid the behavior.