How to balance work, running, health, and a social life

It seems like our lives keep getting more and more full and we are being stretched thin and in about a hundred directions at once.  Whether it's kids, being a caregiver for an aging family member, a career that demands long hours and lots of travel, or a multitude of other things, there's never a shortage of something to take up your time (that you just don't have).  So, how do you balance it all without offending people, dropping the ball at work, or driving yourself to sheer exhaustion?