cardboard case

Yeah, this may sound funny but I'm modifying a cardboard box to be used as a case to house an older Jetway 775 mb, e7650, 2gb ram, and some hard drives. Really just doing this for fun but with not using a metal case, should I worry about the mb not being grounded properly? While the main 24pin connector could help ground it. Should I be worried? This will be a play around system, maybe even a server for some time. I may upload a pic when I'm done

A motherboard only needs to be grounded to the PSU via the 24-pin ATX connector, although you might want to rethink mounting electrical components inside a cardboard box.