One player comes up with a word that doesn't have an obvious opposite. The word is presented and each of the other players individually decides on a word they believe to be the original word's opposite. Players answer by synchronized reveal (see ”Giving Answers” in the introduction) and the opposites are compared. The players who submit the most popular answer win points for the round. Moderatorship then moves to another player.
Some history on this game was written up in the SF Chronicle. Amongst other bits:
Opposites Attract was invented by David Scott Marley, and there has been a continuous game on the Well (www.well.com) since dinosaurs walked the earth.
(Scott Marley is Hudu.)