I used to do IT weekend work a lot. Mostly it was heavy lifting stuff like physical desktop migrations where I would be on or lead a team that would unload a truck, put computers on desks, plug them in, image them, set them up, document stuff for users and move on. I've done this for small companies and huge enterprises. It's common work. Doesn't pay great, but low stress, extra money and gets your resume growing.
Additionally you don`t have time to waste it on beer, so work equals savings :)