Mark Frauenfelder of Boing Boing demonstrates a foolproof spelling-based card trick that will surely impress children (and adults too!). The trick was invented by magician Jim Steinmeyer and Mark learned about it on Greg Ross’ Futility Closet.

The Trick

Remove any nine cards from an ordinary deck, shuffle them, and deal them face down into three piles. Choose any pile and note its bottom card. Then assemble the three piles into one, being sure to place the chosen pile on top.
Suppose the card you chose is the three of spades. Spell T-H-R-E-E, dealing one card face down onto the table with each letter. Place the remaining cards on top of these five and take up the whole packet. Now spell O-F, and again place the remaining cards on top of these two. Then spell S-P-A-D-E-S and place the remaining cards on top.
Now pick up the packet and spell M-A-G-I-C, dealing the final card face up. It’s the three of spades.
Remarkably, this trick will produce any card, from the 10-letter ace of clubs to the 15-letter queen of diamonds.

How it works

 Example: X is three of clubs Start three (5) of (2) clubs (5) MAGIC 1 6 8 2 M 2 7 9 1 A X 8 5 7 G 4 9 4 6 I 5 5 X X C 6 4 2 4 7 X 1 5 8 2 7 9 9 1 6 8

The card value spelling has from 3 to 5 characters. Since the minimum is 3 the X card will always be in position 7 after the first spelling.
OF is 2 characters so the X card now moves to position 5.
Spelling of a suit is 5, 6 or 8 characters. Since the minimum is 5 the X card will stay in position 5 after spelling the suit.
Thus as you can see the X card will be in position 5 no matter which card is chosen.
MAGIC has 5 letters so the count will stop on the selected card.