Hand a deck of cards to a spectator. Ask her to examine it, shuffle it and make sure that it's fair. Then, ask her to remove a card of her choice, and ensure that you have no opportunity to see it.
Take the deck back from the spectator. Ask her to remember her card and also show it to any other spectators.
Hold the deck face down in your right hand and start dropping the cards into your left hand. Ask your spectator to say "Stop" whenever she pleases. When indicated to stop, square up the cards in your left hand and ask her to place her card on top of that pile. This will seem fair, as she had control over when you stopped dropping the cards.
Place the little finger of your left hand over the bottom left corner of the deck. Simultaneously, drop the remaining cards in your right hand on top of the cards in your left hand. Make the act of dropping these cards seem casual. This is best achieved by performing it quickly and letting the cards get a little messy.
Square up the deck. From the spectator's perspective, the deck will look normal. However, you will see a small "break" in the deck, created by your pinkie finger. This is called a "pinkie break". Her card is under your pinkie.
Quickly cut all the cards above the pinkie break, place them on the bottom of the deck, and immediately remove your left pinkie off the top card. Her card is now on top of the deck. To disguise this movement, immediately perform a false shuffle or two, followed by a false cut (see Resources if you do not know how to perform these techniques). This will make the rather obvious initial cut seem part of the shuffle. If performed correctly, the cards will appear mixed and the spectator's card will still be on the top.
Ask your spectator if she believes in ghosts. The purpose of asking this question is to catch your spectator's eye, drawing attention away from the deck, as it is difficult to answer a question without making eye contact. While your spectator is answering, perform a Russian shuffle (see Resources). Put a bit more pressure on the cards than you would do in an ordinary Russian shuffle. This will bend all the cards in the deck forward.
Cut off roughly the bottom third of the deck and, in the act of passing it to the top of the deck, bend it backward. Place these on top of the rest of the cards. This should all be done while holding the spectator's gaze. As you perform this maneuver, explain that while it may be silly to believe in ghosts, on Halloween the air is rife with spirits, and that you are going to attempt to enlist their help in finding your spectator's card.
Put some thought into this bit of patter, and spin it out for as long as long as you need to arrange the cards correctly. The purpose of the patter is to build atmosphere for the impending effect. Feel free to lay it on a little thick.
Hold the deck flat in your hand and extend your arm slightly. Make sure that both you and the spectator are looking down at the deck. By bending the cards in this manner you will have created a break in the deck which is only invisible if viewed from above.
Because the bottom two thirds of the deck are bent downwards, and the top third of the deck is bent upward, by moving your hand only a fractional amount, the top third will slide off the deck and onto the floor. Because the top third originally came from the bottom of the deck, once those cards have fallen, the remaining top card will be the spectator's. The deck will appear to have cut itself. Of course, you had nothing to do with it. It was ghosts all along.
Take two identical decks of cards and remove any one card from the first deck. For example, remove the ace of spades. Discard the pack from which you took the ace.
Light a cigarette lighter and carefully scorch both sides of the card. Be sure to do this in an open area, because the smell of a burning playing card is quite unpleasant. Do this slowly and cautiously. Your aim is not to set the card on fire, but merely to inflict noticeable burn marks on both sides. Be sure to have a bucket of water handy just in case.
This should all be done the day before Halloween. Once the card is suitably scorched and you have made sure to extinguish any burning embers on the card, place it under a heavy book (a large dictionary is good for this) and leave it overnight. You need to do this because cards tend to warp when heated, and you need the card to be flat.
Gather a group of people round a table and explain that you are going to enlist the spirits to perform a seance. Explain that you will not be contacting dead, rather that you will be harnessing the collected psychic power of your guests to perform an impossible feat. Prior to this, you should have placed a large ash tray in the center of the table.
The burnt card should be placed in your jacket pocket. Ensure that you are standing at the head of the table, with a little space between you and your guests. You do not want anyone sitting at your immediate left or right.
Remove from your pocket a deck of cards. This is the second of the two decks from the first step. The ace of spades from this deck (completely unscorched) should be on the top of the deck. Ask for a volunteer and have him select the ace of spades using your card forcing method of choice. If you do not know how to force a card, please see the sources.
Control his card back to the top of the deck using the same method outlined in the previous trick. Once his card is at the top of the deck, top palm it into your right hand (see Resources) and, while placing the deck on the table, slip the card into your jacket pocket and pick up the burnt card, again palming it against the flat of your hand.
With your other hand, give your volunteer some flash paper and ask him to write the name of his card on it. Flash paper is special paper available from all good magic shops which, when ignited, burns itself out very brightly and quickly. It is perfectly safe, provided you use it responsibly, but be sure to read the instructions which come with it. Ask the volunteer to show the other guests what he has written. While he is doing this, casually shuffle the burnt card into the deck.
Ask your volunteer to place the folded flash paper into the ash tray. Then ask your volunteers to join hands and focus all their mental energy on the ash tray. One good tip to increase the suspense is to ask them to chant "Burn! Burn! Burn!" while doing so.
Take your lighter and set fire to the flash paper in the ash tray. It will burn very brightly and very quickly, creating an impressive visual effect. Then, take the cards and spread them out. Explain that what you really wanted them to burn was not the paper in the ash tray but the card in the deck. Leaf through the deck until you find the burnt card. From the spectator's perspective, this is a very powerful effect as you did not see which card the spectator picked.