We have a very full schedule to juggle, as I'm sure you do too. I work full time which involves some travel. My kids are both very active in school and sports. So I have set up a system that seems to be pretty full proof regarding keeping us on track and where we need to be when we need to be there.
1. Keep one calendar ONLY! This is the cardinal rule. Do not have one calendar for your family, one calendar for work, one calendar for your personal stuff. This is just asking for chaos. One calendar ensures that if you are scheduling a dentist appointment for your daughter you can see that you have a work commitment at the same time, meaning you can't take her.
2. Electronic is best. I say this for several reasons. First an electronic calendar (i.e. Microsoft Outlook, Google Calendar) can be easily edited without leaving a mess behind. Second, there is infinite space for notes, addresses, multiple appointments at the same time. Third, it will make it much easier to sync with your family. And last, with smartphones, iPhones, Blackberries, etc., it is easy to carry this calendar with you at all times.
3. Make meetings with your spouse. If you are using an electronic calendar set up everything as a meeting and "invite" your spouse. Have him do the same thing. This way you both have the same calendar. I don't invite him to things that occur within my normal work hours but I do send him travel arrangements. When you accept a meeting invite you have the choice to make your time free or "pencil it in" on your calendar meaning that a dentist appointment for your daughter that your husband is handling the transportation on will not make you look unavailable for work meetings. This has been a lifesaver for us!
4. Make up a Week at a Glance chart. I made a chart a few years ago called "Sloan Family Week at a Glance." It is very basic in design -- just seven columns for each day of the week that runs Monday - Sunday. I laminated it so I can write on and rinse off each week. Sunday evening I sit down with my Blackberry and I write down everything we have going on and it gets taped on the front of the refrigerator. This is great for everyone, including the kids, to see what is going on. It also helps with meal planning, if one night is jam packed with everyone going every different way, its probably a good night for crockpot chili or leftovers.
So that is how I manage the very busy calendars of four very active people in my house. If you haven't used Google Calendar or Microsoft Outlook, play around with them. I'm not terribly familiar with the Google one but that is what my husband uses and it syncs to his Sprint EVO. I use Outlook which I LOVE! Each morning when I get to work I also print off just that one day and carry it with me. One other perk to going electronic is you can schedule YEARS in advance if you want to. And yes, sometimes I will know a year or more in advance of something that needs to go on the calendar. If you use paper you can't write it down until you buy that year's planner.