Chipmunk Forum is a small yet flexible and fully featured forum system. It has unlimited categories and forums, staff only forums, read only forums, 4 levels of permissions. Smilies, word filters, BBcode, Ip banning, e-mail ban from registration and much more.
You may use chipmunk scripts for free on any personal or commercial site. You may modify the code and release any hacks or mods of it as long as the copyright notice to chipmunk scripts stays intact and the mods/hacks/skins you release are free. If you wish to take off the copyright, re-brand, or make your own commercial software off of the code of chipmunk forums, please contact me at firstname.lastname@example.org