The fourth graders in our school go to camp every year supported by these events.
People can pay for their birthdays, anniversaries, or other special events.
Set up sections for businesses to advertise in the calendar and determine advertising fees. You may want to limit how many names can be on one date. You could have names printed in light florescent colors so that calendars can still be written on for personal scheduling. Once you have collected enough money to cover the printing cost and make a profit, have them printed. Also take orders ahead of time for this calendar and charge an appropriate amount.