Before the turn of the century and later, a type of act called "second sight" in which the magician worked with a "medium" (typically his wife) was very popular. The magician would walk around the audience holding up various objects supplied by audience members, and the "medium", sitting on stage, blind folded, would precisely name and describe the objects to exacting detail.
In the mid-90s I wrote a Macintosh program, Orville, in which the computer plays the part of the medium. It uses the same time-honored methods for achieving the effect. When presented as an experiment in "Artificial Intelligence", the program has fooled some fairly astute, technically savvy friends of mine.
Since then, I have created a number of other computer-aided magic tricks, which may be found strewn throughout my various websites. These include:
Metascope - The Mind Reading Kaleidoscope (discontinued)
I've provided custom software to a small number of working magicians (most notably Simon Winthrop) for use in their acts.
Tarot Decks and Old Playing Cards
In 2002, I did some work on a card trick that involves Tarot Cards. In the course of working on it, I read a lot of the material on the web regarding the history of Tarot Cards (which were originally created to play a bridge-like game) and bought a few decks. My favorite modern deck is the Victoria Regina Tarot by Sarah Ovenall, which is a black and white collage deck reminiscent of Max Ernst.
No, I do not actually "believe" in this stuff.