The best card trick I've ever learned (which I made a lot of money on in high school and college) is below. My high school typing teacher taught it to me. I'm nowhere near as good as your friend, but feel free to try it out if you wish - it's actually quite easy.
Take a deck of 52 cards. Separate them out by suit - 4 separate piles - arrange each pile in descending order, from Ace to 2.
Then, the object is this: Spades, hearts, clubs, diamonds, descending by multiples of 3. So you'll start with the ace of spades, the next card you'll add below that will be the jack of hearts, the next card will be the 8 of clubs, the next card will be the 5 of diamonds, and so-on, until you've built your pre-stacked deck of cards.
Now, when presenting the trick, first of all, spread all the cards across a table, so that everyone can clearly see the deck isn't stacked, as it certainly won't appear to be, and I've never been called out on it before. Then, once they're convinced the deck isn't stacked, you can even shuffle the cards. Not the traditional shuffle whereby you have 2 separate piles of cards and shuffle them, but the kind of shuffle whereby you take parts of the deck of cards and remove some from the bottom and then replace them on the top. Do this as many times as you wish. Then, even offer the other person to cut the cards. None of this matters. The order of the cards will not have changed.
Just remember, spades, hearts, clubs, diamonds, in descending multiples of 3. Then, spread the deck of cards out in your hands, and offer the person to choose any card at random. After they've chosen their card, just place your finger on where they pulled the card from the deck. Then tell them something ridiculous like, "Look at your card, but don't let me see it, then go to the other side of the room and place the card face down under that coffee cup, or put the card under your shoe - or whatever." Anything to divert their attention from you for a few seconds.
While they're doing this, you quickly check where you've placed your finger to see the card which is above the card the other person chose. You then put the deck down on your desk (or wherever) while they're placing their card in whatever ridiculous place you've told them to.
So now you know the previous card. Say for example it's a 9 of clubs - well then YOU know their card is the 6 of diamonds. Challenge them to a bet that you can guess the card. Rinse and repeat. I've never had anyone in my life that's been able to figure this out. It amazes them, yet it's so simple.
Including @Flintstone on this post, just since he's been such a good contributor.
Good Lord, where do you come up with this stuff? You kill me with laughter! Won't even consider this an official entry - will just send you 100 XRP on the side (having nothing to do with the contest). Will send it it the morning. Will send it from my spare wallet, already have your info. My goodness you make me laugh so much. Thanks.
A wealthy man had a little boy. For some reason, his first words were "ping pong ball". When the boy was old enough to speak, and understand birthdays and gifts and such (about three years old), he asked the boy "So son, what would you like for your birthday this year?" The boy said, "Daddy, I would like a pink ping pong ball." Father said "That's it? No trucks, no trains no puzzles?" The boy said "No, just a pink ping pong ball.
So the father gets him the pink ping pong ball and wraps it up. The boy is absolutely delighted. He takes the pink ping pong ball to his room, and the pink ping pong ball is never seen again.
A day before his 15th birthday, asked by his father, `Well my son, what would you like for your birthday?'
The son hesitated a moment and his father's thoughts leapt ahead to a new computer and similar things. However, his son had had a new computer only recently and could have a new one any time he wished.
Finally, the son said, `Father, I have everything a boy could wish for, but there is one thing I would really like. I would love to have five pink ping pong balls.
The father was rather astonished at this wish, but said, `If it is pink ping pong balls that you want, a pink ping pong balls you shall have.
And so, the next day, the son was given as his birthday presents five pink ping pong balls.
The boy took the pink ping pong balls to his room and the next morning the pink ping pong balls were gone. The father was mildly surprised but decided not to say anything. The pink ping pong balls, however, was never seen again.
The next year, a day before his 16th birthday, the father asked his son what he would like for his birthday.
`Father,' replied the son, `I have everything a boy could possibly wish for, but there is one thing I would really, really like. I would love to have a ten pack of pink ping pong balls.'
The father was more surprised than the year before, but kept his curiosity at bay, for he knew that his son had a right for privacy. He said therefore, `If it is a ten pack of pink ping pong balls that you want, a ten pack of pink ping pong balls you shall have.'
And so, the next day, the son was given as his birthday present a ten pack of pink ping pong balls.
The boy took the ten pack of pink ping pong balls to his room and the next morning, not a single ping pong ball remained, merely the empty husk of the ten pack. The father wondered where ten pink ping pong balls might disappear to, but decided not to say anything. The pink ping pong balls, however, were never seen again.
The next year, a day before his 17th birthday, the son was asked by his father what he would like for his birthday.
`Father,' said the son to this, `I have everything a boy could wish for, but one thing would make my happiness complete. I would dearly want a carton of pink ping pong balls.'
The father was beyond surprise, but decided to make sure he had not misheard. `A carton of pink ping pong balls?'
`A carton of pink ping pong balls,' the boy confirmed.
`I can't understand your fascination with pink ping pong balls,' said the father, `but if it is a carton of pink ping pong balls that you want, it is a carton of pink ping pong balls that you shall have.'
And so, the next day, the boy was given as his birthday present a carton of pink ping pong balls.
The boy was delighted and took the carton to his room. The next day, miraculously (as if by magic, even) the pink ping pong balls had all disappeared.
`Dear son,' said the father, `I must ask now, what do you do with all those pink ping pong balls?'
The son, however, was reluctant to tell him. `Please humor me, dear father.'
The carton of pink ping pong balls, however, was never seen again.
The next year, it was clear that the son would get a car, but the father felt that, perhaps, his son also had some other wish apart from the obvious. So, one day before the son's 18th birthday, the father asked him whether he had a special wish for his birthday.
`Dearest father,' the son started, `I have everything a young man could possibly want, but there is one craving in me. I would, more than anything, want a warehouse full of pink ping pong balls.'
One of these years, his father thought, I should get to the bottom of this. However, he decided to humor his son's wish. At least he had been wise enough to buy shares in a pink ping pong ball factory.
The next day, the son was given the address of a warehouse where all his new pink ping pong balls were stored. The son was delighted and decided to spend the next night in the warehouse rather than at home.
The following morning, the son stepped out of the warehouse, but it seemed to be empty otherwise. The father had a closer look and indeed, apart from empty cardboard boxes, nothing was left inside the warehouse. No pink ping pong balls were left.
The following year, one day before the son's 19th birthday, the father braced himself for another warehouse of pink ping pong balls. He asked his son what his deepest desire was and he had not been entirely wrong.
`Father, you have made me very happy these last years and this year I ask of you a shipload of pink ping pong balls if at all possible.'
It was possible, if only because the father had by now bought each and every factory of pink ping pong balls in the country.
The next day, the father took his son to the harbor and showed him a huge tanker and told his son that there were millions, billions, trillions of pink ping pong balls in there.
`Father,' the son said, `You've made me very happy yet again.'
That night, the son spent on board the tanker.
The next morning, not a single of the pink ping pong balls could be found, but the son was happy.
A few days before his 20th birthday, however, the son had a terrible road accident and was taken to the hospital.
His father visited the young man in hospital. `My dear son! Can I bring you anything to make you feel better?'
Weakly, the son sat up in bed. `Father, dearest father, grant me this wish; just one ten pack of pink ping pong balls.'
The father held his son's hand tightly. `Whatever you wish my son, but I have to give you one condition. Even if it may be embarrassing, I must know what you did with all those pink ping pong balls.'
`Very well, father, but please indulge me first. I will tell you whatever you wish to know after you have given me the ten pink ping pong balls.'
The father thought that was fair enough and the next day brought his son the ten asked for pink ping pong balls. The son smiled weakly but seemed too weak to talk.
Son, I leave these pink ping pong balls with you and shall come back tomorrow to ask of you what you have done with all those pink ping pong balls.
The son nodded weakly.
The next day, less than surprisingly, no pink ping pong balls could be found in the son's hospital room.
Now, my dearest son, apple of my eye, treasure of my life, please tell me what you did with all those pink ping pong balls, the father requested.
The son nodded and the father gripped his hand tighter.
`I-' the son started and sat up a bit, swallowing with a dry mouth.