I love my windows calendar that came on my laptop. I use this as my main calendar now. You can set reminders so that it will pop up and remind you of appts.
I also use it to plan my meals. It's wonderful, because if things change, you drag that days meal to another day. It's just an easy drag to a new day. You can rearrange etc.
So if you are supposed to have meatloaf today and someone invites you out to dinner,you decide you don't want to cook today and order a pizza, or you decide that you are not in the mood for meatloaf, you can drag it to another day and drag what you want to that day. I plan my meals for the week and then I grocery shop by what we want. I ask the boys if there is anything special they want and I add it to the calendar for the week.