Step 1: Set the Deck
Setting the deck is required for this trick, but it's very simple and can even be done in public without drawing notice.
1) Remove two sets of two cards from the deck. The color of all the cards must be the same. Each set must contain the same number or suit, depending on how you've grouped them. Black seems to work better, and I prefer using the 5 and 9. If you do the same, you will need to remove the 5 of clubs, the 5 of spades, the 9 of clubs, and the 9 of spades.
2) Place one of the cards on the bottom of the deck. In this example, I placed the 9 of clubs on the bottom.
3) Set the card opposite number AND suit at the top. Place the final two cards atop it.
Step 2: Begining Your Presentation
Walk up to your viewer and ask to show them a card trick. (Note: THIS IS NOT A GOOD WAY TO MEET WOMEN!) It's best to do it for someone you know. Flip the top two cards face up onto the nearest surface. Say "OK, we have a 9 and a 5." Do not point out suit. Don't give your viewer too much time to look at the cards. After you have said your line, flip the cards over and hand them to your viewer.
Step 3: Get the Viewer Involved
People tend to think your trick is more realistic if you let them help. Have them insert the two cards into the deck whereever they like.
Sometimes, they'll try to put a card on the top or the bottom, so if they do, give them a "look" and ask them "Do you really want to put that card there?" Usually, they'll reconcider. If they don't, flat out tell them to put it somewhere else. Promise them it will make the trick more interesting. Most of the time, however, they won't try it anyway.
Have them square the deck.
Step 4: The Reveal
Now it's time to look amazing.
Grip the top and bottom cards between your thumb and first finger. Push your wrist back and 'throw' the deck (into a chair, preferably). The trick is to hold the top and bottom cards while losing the rest. Flip the cards over to reveal: Not the same cards! (Gasp!) Relax; most everyone will not notice the switch (especially if you're fast enough). Actually, I've never had anyone figure this out (the first time I showed them).