I'm in my early 40s now and I don't juggle or balance as often as I used to, but I still find time every now and then and enjoy dusting off the skills. These kinds of things can also surprise and impress people, or encourage others to give them a go, or best; get surprised when someone else also has the same skills. It's like an instant bond. That knowing nod shared when people understand the work that has gone into learning these stupid things.
So yeah.. my piece of advice is, while you're young and have more "spare time"; spend some of it on learning some weird physical skill.
Others have mentioned learning an instrument... and I've sort of regretted putting my time into learning physical "tricks" rather than say the guitar.. So maybe my advice is to do both :)