Here's how it works:  First, as you enter the room, you drop your business card in the "bingo box," as does everyone else. You are then given a "bingo card," and you write your name in the center square.   Next, you circulate with everyone throughout the room. To complete the card, you need to meet 24 other people, collect their business cards and have them write their names in the open squares.   Later, someone calls off the names on the business cards that everyone dropped in the bingo box when they arrived. Regular bingo rules apply thereafter. The winner is the first person with five names in a row, either across, down or diagonally.