PSI stands for Psychology Slander Intuition. This is a party game in which a person's character is described as a comparison to an object. Player's counters are the 7 deadly sins, Sloth, Avarice etc. You draw a Personality card, giving a clue to the type, eg sports, politician etc, the next player draws a PSI card and asks "If you were a Language/ Salad Dressing/Letter Of The Alphabet, which would you be?". You're supposed to answer as if you were the personality and the questioner is supposed to guess who you are. If they guess correctly, they advance along a track, if they fail, the next player tries another question and so on. If no-one guesses correctly, you reverse down the track for giving bad clues. The hilarious party element is that the Personality cards include the Sins, so you would answer as if you were that player.