Can I rename the SampleEvents and SampleProjects tables?
Yes. But after you do, you'll need to edit the script "Load Source Settings at Startup --- Describe Your Sources Here ---" to tell it the name of your new table occurrences. The script has very simple instructions at the top and will walk you through changing it.
You'll edit this script whenever you change the name of the events, projects, or phases table occurrences for any source in the calendar, or if you change the name of the layout used to display event details (when you click on an event in the calendar).