This card trick is amazing yet simple. It was created by a guy named Andy Field so I can't take credit for it. Here is the link to his website...
Step 1: Dealing
First have one of your audience members deal out as many cards from the top of the deck as they want. While they are doing this count how many cards they lay down and memorize that number. For example let's say they lay down 12. Then have the audience member memorize the last card they put down. In the picture for this step I have the card face up, this cannot happen during your trick. Now stick the rest of the deck back on top of the pile your audience member just made.
Step 2: Repeat
Repeat the last step with another audience member or the same audience member. Let's say this time 16 were layed down. Now you should have two numbers memorized, 12 and 16.
Step 3: Key Card
After all the cards are back In the deck tell the audience that you are showing them that there is no way that you could know where the cards are. As you lift the deck up peek at the bottom card and memorize it. Without this card you will not be able to do the trick. For this example the bottom card is the 4 of hearts.
Step 4: Cutting
Have another audience member cut the deck wherever they want and then stick the bottom half of the original deck onto the top of their cut. Tell the audience that now there is really no way that you could tell where the cards were.
Step 5: Finding the Cards
Now you will have to go through the deck and find the 4 of hearts. Once you find it count 16 cards, because that is the amount from step two(4 of hearts counts as the first card) The 16th card will be the second audience members card. Then count 12 cards, because that is the number from step one. The 12th card after the 16th card will be the first audience members card. You have to remember that the numbers are in opposite order at the end. If you run out of cards when you are counting carry over to the top of the deck again.
Now you can enjoy amazing people with this awesome trick!