For our pals without the great book, Chain Letter was probably based on an old party game where a category was given, then players on teams would give subjects that fit the category, but the trick was...the first letter in each new answer had to be the same as the last letter of the answer that preceeded it. Two teams with two players each, and there was a tricky strategy that made the game interesting. Team players sat side by side -- like A1 - A2 B1 - B2. Say the category was "things in a medicine chest", and you started with player A1. He would name a subject (quickly to avoid being beaten by the buzzer), such as
"aspirin". Then his teammate has to come up with the next answer, which must start with "n" - "nose drops" - play passes to B1, then B2, back around to A1, and on it goes for three minutes. One of the tricks of the game was that if you were the A1 or B1 player, you wanted to be careful that you didn't give an answer that stuck your teammate with a last letter that would be impossible to play. Any time a player was stuck and the chain was broken, the opposing team scored a point. If you were the end player on your team, you tried to stick it to the opposing team. Each player had only a few moments to think of an answer that both fit the subject and either help or hurt the player next to you. So with the above example: A1 - aspirin/ A2- nose drops/ B1 - shaving cream/ B2- mercurochrome/ A1 - ex-lax ...and A2 is stuck with an X!
Time buzzer goes off, the B team scores a point. The A2 player resumes play with any new answer, and the play goes on until time for the round ends. Team with the high score wins. A little cerebral and quite clever.