Holiday/Breaktime Bedtimes?

Only a few "normal" days left until Christmas and a school break for kids and perhaps for parents, too. How do you all handle bedtimes when your kids don't have to be out of the house at the same time they usually do?

Post with your kids' age, because I'm guessing this varies a lot by age.

I used to keep bedtimes as close to usual as possible, but now that my kids are what I call "grown-up kids" I let them stay up as late as they want with the understanding that they'd better be able to function the next day, or bedtime gets rolled back the next night.

Bonus question: Do you think excess sugar consumption at holidays affects your kids' sleep and general behavior?