I find that most people in my life have at least one "thing" they are collecting. It is often an insight into their personality and it is fun to hear people talk about something they are passionate about.
I've gotten into selfhosting lately, and my newest obsession is setting up a browser based emulator that I can access from anywhere and basically play 3 games - contra, balloon fight, and caddilacs & dinosaurs
Edit - I mean play legally backed up copies of these games :)