Of course, you want to enter events when you are unavailable for meetings like teaching time. But how do you enter events that you want to remember, such as your kids' soccer game; but don't want those events to indicate you are unavailable for meetings?
School events, such as teaching time, coverages and the like should be entered on the school calendar, either through the web interface (calendar.google.com) or through Apple's Calendar application.
Events you want to create, however, that are of a personal nature (kids' soccer games) should be stored on a personal calendar. Here's how to create a personal calendar in Apple's Calendar application and on the Google/GMail web interface.
Creating a personal calendar - Apple Calendar application
Creating a personal calendar - Google's web interface
Open your calendar at calendar.google.com and click the drop-down arrow next to "My Calendars". Select "Create New Calendar".
Click "Create Calendar at the top and that's all there is to it. This calendar will be available to schedule events but those events will not show you as being "busy" during those times and, thus, available for invites.
In about two or three minutes, you'll see this new calendar show up in the Apple Calendar application.
Now you can use either the web interface, or the calendar app to record events to the personal calendar.
The nice thing about this calendar is that should your computer crash and require a rebuild, you won't lose all your personal events like you would if you COULD create a local calendar on your laptop. So, I don't see a problem with not being able to create a personal calendar with the Apple's application.