Send out your monthly newsletter advertise the BINGO game on your facebook, twitter, etc. Have them come to the office to pick up their unique BINGO card. As they follow you and/or log in daily to these sites you post the numbers drawn daily if they have it on their card they mark it off once they have a BINGO they call or come by the office to pick up their winnings. This does several things gets them active in the community, creates participitation and gets them on your social networks to read whats happening at your community.