The only, but only, magic trick I've ever learned is a card stunt taught me by my father when I was nine. He showed it to me several times and I didn't get it, undoubtedly because I was looking so hard for something clever. (Don't we all?)
It's done with a standard deck, although it's well to strip out the jokers just in case. Shuffle the deck awkwardly while pattering about how inept you are with cards. (This works well for me because - yeah, you knew this - I'm genuinely clumsy with cards.) Sneak a look at the top card in the deck as you fumble, patter, and otherwise misdirect; we'll say that it's the ten of diamonds. Then solemnly address your victim, "As you know, there are four suits in a deck of cards: hearts, diamonds, clubs, and spades. Pick two of those." The sucker picks hearts and spades. Quickly and authoritatively now: "All right, that leaves diamonds and clubs. Pick one of those." Uh, diamonds says the sucker. "Good! Now" with much brow wrinkling and grunting, as if this was REALLY DIFFICULT "of the (ugh! ergh!) ten, jack, queen, and king of diamonds, pick two." Ten and king. "Good again! One of those!" King. "That leaves the ten, am I right? Ten of diamonds? Eh?" Uh, yes. "Here ya go, kid!" as you toss down the ten of diamonds, dealing off the top of the deck, no sleight of hand involved.
If the sucker picks diamonds and spades, of course you instantly require him to pick one of those, rather than pull the "that's leaves" caper. Similarly with the trick of directing him to the denomination of the final card.
This one can be elaborated with a 3 x 3 layout of facedown cards, directing the victim to turn over the desired card by the same method of that-leaves or one-of-those.
You can repeat this one by memorizing several cards at once. I've also used a planted deck that I'd had a look at earlier and put away in a drawer, actually EXTRACTING IT FROM ITS BOX AND NOT EVEN SHUFFLING IT! Astounding!
Well, it works on nine-year-olds.