Juggling is one of hobbies with the highest ratios of being able to impress random people versus the actual effort you have to put in, and I generally find I never forget 3-ball stuff I learned as a kid. It's also as good as a long walk for getting you out of your head when needed. Shout out to anyone that remembers the Mushy Pea juggling shop in Manchester many years ago, where I learned all sorts of circus skills.
Rubik's cubing is another. Most people here with enough logical aptitude to be programmers could probably learn a beginner method in a day or two. I'll pick up a cube anywhere I see one scrambled, solve it in a couple minutes, and then the last flourish is to leave it in the checkerboard pattern. I also juggle, and the result of the combination is that approximately every single person on Facebook has posted to me th…
Even sided cubes are the hardest because they have issues with "parity" that are only uncovered near the end of the solve and can be quite tedious to fix (at least imho).