A King of Spades
A Queen of Spades
An Ace of Spades
An Ace of Diamonds
Step 2: Cut the Card (literally)
Position the Ace of Diamonds at, lets say, 30 degrees. Draw a line and cut it in two. Then cut 3/4 of a centimeter of the bottom of the card.
Step 3: Tape the Card on the Queen
Place a piece of clear tape on the back of the sliver. Bend back the tape and stick it on at an angle that looks like you are fanning it out.
Step 4: Baffle your audiance
Now slip the Ace of Spaces under the sliver so that most of it is still sticking out. Cover it with the King and show everyone your cards.
Step 5: Now for the "magic"
Take the middle card our (Ace of Spades) and make sure nobody see it. Show the audiance that you took a card still hiding the flap. They think you took out the ace of diamonds. Now pick up the ace of spades. It magiclly changed!