http://www.hawaii-county.com/parks/p...immingpool.htm
see also:
http://www.hawaii-county.com/parks/parks.htm
http://www.skateboardpark.com/skateb...rk.asp?ID=3524
(In Volcano...)
http://biaug.com/20/keaau-youth-busi...grand-opening/
(My SO helped design the recording studio part of this center, but we haven't really heard much about how students get involved....it has the potential to be something really interesting, but I don't know much about what is happening with it right now.)
These are a couple of links that may interest you....many students are involved in sports leagues or activities through school. Dance, hula esp, and music lessons are easily available in and around Hilo...there is also a YWCA in town that offers classes for younger children and has a pool:
http://www.ywcahawaiiisland.org/contact.html
I don't have children, so am reporting what the children of friends are doing...Other parents will probably have more insights!