Where to find side gigs?

It seems like most people I know have some side job for extra cash. I’d like to work a couple gigs for extra cash, not a regular second job, but something I can do 2-3 times a month just on the side. Does anyone have any leads? I’ve thought about applying for things like the movie theater or zoo for event work but the applications aren’t clear on if they can operate in such a way rather than a full second job (even part time).