The Age cards are one of the oldest of Magic effects, – one many of us learnt as one of our first effects in a magic set.
In case you are not aware of the effect, you place 6 cards with different numbers on them in front of a spectator. The spectator merely points to the cards which show his age, and you can immediately reveal the spectator’s age. Or use a more subtle method, having the spectator place the cards that show his age in his pocket as you turn around, and you can still reveal his age. The only catch is that this does not work for senior citizens of 65 years or more !!!