In pairs, the first person says the first letter of a word which is in their head. The pair then needs to say a second letter of a word in their head. They continue but they need to avoid making an actual word (4 letters or more) to win. e.g. P-O-R-C- now even though the person may be thinking porch, it is the responsibility of the next person to use the word e.g. porCELIN to avoid losing. There is also the option to challenge the other person if you think they chose a letter but did not have an actual word in mind. If they did, you lose. If not, they lose. Kapish? Its a fun game to play quietly with a mate either on the bus or on an aeroplane or in a boring lecture!