Instructions for a trick by Rick Maue, very interesting. While the manuscript arrives with some cards, it can be presented also with normal business cards, written on the spur of the moment.
Basically, a spectator choses an emotion out of five, then she assigns all emotions to other five spectators, sight unseen, and the magician finds who is sharing the same emotion with the spectator.
While the effect is quite procedural, it can be streamlined and the effect enhanced with a more dramatic revelation. It is a great idea anyway.