If you open the Weekly Planner template that ships with the ClarisWorks Home Pack template set, you may have difficulty using it. Page 2-20 of the instructions for the Home Pack indicate that you should "Enter the date of the Sunday starting the week ...", but if you attempt to type a date into cell C6, you will get an error "Some cells are locked."
All that you have to do is Unprotect the cell (Choose Options menu, Unprotect cells), and you can type in the new value without a issue.