When should you hold community events? In the United States Thanksgiving is a major event and often the time families travel to be together. It is also during school term. Every year for nearly a decade, Valley Christian School
has "recognized grandparents as among the important blessings in their students’ lives with a half-day of activities just before Thanksgiving, when relatives might already be visiting from out of town." While hosting events during a busy time of year may not be ideal if it means more will attend then it can be worth considering.
Another school I know alternates between performing a School Musical one year and Grandparents Day the next to help ease the burden on staff. When scheduling a school event consider what larger sporting or community events may either clash with or complement yours.
Source: Grandparents honored for their legacy, love at Valley Christian School