1) Count out 30 cards face up. Remember the 10th card. (Lets say that it is the joker.)
2) Deal five cards in a vertical row on the table, starting a couple of feet away and dealing toward yourself. Then deal the other 25 cards in a circle around the five cards. Assuming that the circle is a clock face, you deal the first card at 7 o'clock and continue clockwise until you deal the last card at 5 o'clock. Leave empty the space corresponding to 6 o'clock.
3) Have a sp
ctator name any number between 6 and 29 (let's say 13).
4) Count to that number, beginning with the top card in the vertical row and counting toward yourself. When you reach the bottom of the vertical row, continue the count onto the card at 5 o'clock and counter-clockwise up the right side of the circle. When you complete the count, start the count again with that same card, this time moving clockwise. But when you reach the bottom of the circle, instead of going up the vertical row, continue counting around the circle up its left side. No matter what number they named, you'll always complete the count at the 5th card from the bottom of the circle on the left side. This 5th card will be the 10th card that you remembered from the start (the Joker in this case).
5) Let them see the card (you know it is the Joker) and let them shuffle the cards.
6) Make 3 rows of 10 cards face up and ask which row their card is in. When they point to the row put away the other 2 ones. Remember the card's position in its row (lets say that it's the 4th card). Put the 10 cards on top of each other without disarranging their positions. Deal them face down on the table in any way you like, but remember the position of the 4th card.
7) Ask someone to point out a card. Remove any card except the 4th one. (Make it look like you have a system.) This way you let them think that they pick the cards, but you do it for them.
8) When only one card is left it will be the 4th one, which is the Joker! This trick works great!