Ask HN: Sysadmins – what’s your side project?

Recently I’ve changed emplyoer and I’m no longer blocked from opening my own business. I used to have several clients few years ago, but I was forced to close my little company after I joined one of the top corporations. I do Unix and Linux for more than a decade. I’d love to reopen, but I’m not sure what to focus on at the moment. What’s your side gig?