I would encourage all clubs that choose to form; it is a good way for the students to get involved in the school. Skateboard club could be tricky as skateboarding on campus is not allowed and presents serious liability. However, we have an automotive club that goes drag racing, so many things are possible.
One thing you can do is give them a cool place to store their skateboards –
If liability is an issue, you can make it part of their club charter that they will not skateboard on campus. Additionally, you can get special insurance for the club. We purchased a supplemental insurance policy for our automotive club from K&K Insurance. Your SISC representative can put you in touch with the local insurance broker to find the proper coverage.