The problem today is that the younger crowd is all about social media and their handheld smartphones or video games.
I interact with kids sometimes and occasionally expose them to things they've never experienced such as making paper airplanes, playing with a big superball, or throwing a small Frisbee (fling rings are easy for even a 6-year-old to throw). Sometimes I can tell certain children have never played with a ball. There's nothing like witnessing a kid's joy the first time they catch a ball - the look of shock and pride on their face is priceless. There have been times I've felt guilty that I was the one to experience it, instead of their parent.
Although a few kids might collect cards of various types (Magic the Gathering & Pokémon) collecting physical objects seems to be quickly dying. Most kids are not exposed to collecting objects as in previous times, such as stamps and coins and seashells and rocks. The shell collection I kept in a cigar box was one of my most cherished things as a kid. But I'm glad to see that Hot Wheels are still around, even if some are plastic. I think there are some die-cast. And I guess there are some small figurine type collectibles I see around sometimes.
Recently I showed an 8-year-old how to make a disappearing knot on a rope (a tightened slip knot).
He was enthralled & spent the next 2 days showing his family and friends the trick in fun dramatic ways.