Preparation: None. The Thumbs Game is a quick, fun and easy game to play with no preparation required. This game can be played in the background while you and your guests enjoy the rest of your dinner party. In fact all you need to play this is your left thumb.
To Play: You simply explain the rules and away you go. You tell everone that you will start off the game.
After a while (give it a good few minutes) and trying not to let anyone notice, you quietly place your left thumb on the edge of the table. Then as soon as anyone notices your thumb on the table they must do the same thing and place their left thumb on the table as well, also trying not to let anyone notice.
The last person to notice that everyone else has placed their thumb on the table is the loser and could pay some sort of forfeit, (you will need to have a few ready). If you don't like the idea of forfeits then just skip that part. The loser then starts off the next round after a suitable period of time has elapsed.