Two sets of small discs, or chips, are shown.    One set is red, with a different colored spot on each chip, and the other set is black with matching colored spots.     The mentalist takes one set, and puts in a line on the table, spot side up. The other set is mixed up with the spots facedown, and the spectator places his chips, the color sight unseen, one on top of each of the performer's chips.   The performer emphasizes that the odds of one correct match are 1 in 4, two correct 1 in 16, three correct 1 in 64, and four correct 1 in 256.    (I realize this is not really true mathematically since if three are correct, then the fourth must be, but just don't try this patter on your local Math professor, who would know the real odds are 1 in 24...)      When the four chips are turned over, it is seen the four colors match exactly. 

Chips can be casually examined if you so desire, but it never seems necessary.  The spectators have handled them and are simply amazed at the 4-for-4 prediction miracle.