Show three cards (two black and one red) and tell the spectator to follow the red card. Flip them over and mix them up VERY SLOWLY. There is no sleight of hand... it's clear that the middle card is the red one. However, when you flip it over, it is a blank card with a message.

The trick comes with a blank card for the ending. You can write whatever message you choose on it. Some examples are:

FAMILY FUN EXAMPLES:
Fooled you
Gotcha
Red Card (written on the blank card)

ADULT EXAMPLES:
Wanna fuck a magician?
Give the Magician a kiss.