If you are looking for new, I would recommend playing with proxmox. I was using docker containers to self host things like jellyfin, forgejo, and bookstack until a couple friends turned me onto proxmox. Really interesting tool. Now I can isolate my data and open ports to run little game servers for my friends.

If you want to play with something old, but likely new to you, picked up an e-waste laptop and started playing with OpenBSD. I am trying to build out a desktop environment and theme for myself. Its a bit of a learning curve since it’s Unix, not Linux, but I have been learning a lot and enjoying my time shaping an OS.

My brother was telling the “What’s black and white and read all over?” joke to our niece, and she asked what a newspaper was.