Offer to share an apple with someone, then split it in half with your hands. It’s easy once you figure out the technique.
Dollar bill origami. Ask someone for a bill, fold it into a T-shirt or whatever, and give it back to them.
Wear a ring (stainless steel, not gold) and use it to open bottles with your hands.
Obligatory Bob Mortimer https://youtu.be/F21mTojMCAc
If you can solve a Rubik’s cube, normal people will think you are a genius. On the other hand, actual cubers correctly assess that I am a dumbass if they see me do it.
I know exactly one party trick based on mathematical group theory, which I have actually used to impress non-mathematicians at a party.
There’s a concept called the “center” of a “group”, which is the set of operations that commute with every other operation in the group. The center always contains the identity operation of doing nothing. The group of scramblings of a Rubik’s cube happens to contain exactly two elements in its center: the identity, and a move called the “superflip” which takes a little bit of effort to memorize how to do, but it’s not so hard. Much easier than actually solving a scrambled Rubik’s cube. It’s like you do a simple move repeated 4x, and then you do that whole 4x set 3x with some rotations in between. Not terribly complicated. Importantly, once you memorize it it’s not difficult to do just by feel, since it’s a fixed sequence of mechanical motions.
So, the party trick goes like this:
You have a Rubik’s cube that is exactly a superflip away from the solved state. You hand it to an unsuspecting party guest and say “go ahead and make one or two turns” (it’s important to say something like “one or two” because if they do 3 the trick becomes challenging, and if they do 4 or more it might become impossibly difficult unless you’re actually good at solving Rubik’s cubes, which I am not). They take this obviously unsolved cube and make a couple more moves so now it appears even more scrambled.
You take the cube back and do the superflip behind your back, without looking at the cube.
Then you move the cube out from behind your back, and at the same time (trying to be slick about it) you undo the one or two moves remaining before it is solved. Everyone gasps and say “omg he solved it behind his back” (when really you did no such thing).
This works because if S is the superflip and X is the simple moves they did to it, S X S is equal to just X because S commutes with everything. (S is also its own inverse, so that S S = 1.)
Right? I can solve one in a minute to minute and a half. By normal people standards, impressive, by cyber standards I’m laughably slow.
I’m cool with that
If you smoke, the smoke waterfall is neat and easy.
Take your pack of cigarettes and pull the cellophane down to create some space between the cellophane and the box. Using your lit cigarette, carefully melt two holes on the lengthwise ends of the cellophane, and then push the cigarette lit end first into one of them. If done right, the smoke coming off the cigarette will make a little waterfall and pool of smoke.
Maybe not impressive but it is funny to draw 2 pounts at specific locations on a hand and then “eating” stuff by moving the “middle” thumb joint ud and down so it looks like a mouth.
