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.