But those that do consider it a once-in-a-lifetime opportunity for their children to experience the life of a princess, if only for a week.

But I think it's a golden opportunity to really think about what is important in your life, and weed out the things that don't really matter.

This is a chance once in a blue moon.

Even if your interview for the job of a lifetime went well, don't freeze your job hunt while you wait to hear back.

Sex marathons, that last a few hours or even all night, happen once in a blue moon for most couples.