I think we've all read the articles about being efficient. You are in the car with your children on the way to your son's soccer practice. Thank carefully before you begin living your life as an efficiency role model. Too much multi-tasking leads to stress. Perhaps it would be wise to think of more ways of relaxing than multi-tasking.
Life is hectic enough without making it more so.
If you are so busy that you don't have time to get everything done, you might want to look a little closer at all you are trying to do. Sometimes you have to let things go. You can even wear a dirty sweatshirt. It won't kill you.