Hmm, I guess coin collecting? I've always enjoyed that since a young age. Both of my brothers and I started with collecting U.S. quarters and then expanded into foreign currency. But I feel like a lot of young people would find such a hobby boring.
I really enjoy older music (From classic rock to classical). I play a bit of guitar and saxophone. I know how to play and genuinely enjoy chess. I have a minor coin and knife collection. All of these interests exist among people my age, but the amount of people into them I feel has declined.