Tiki Wiki   (link)

http://tikiwiki.org/TikiWiki
http://doc.tikiwiki.org/tiki-index.php?page=Features
Tiki CMS/Groupware (aka TikiWiki) is a powerful open-source Content Management System (CMS) and Groupware that can be used to create all sorts of Web applications, Sites, Portals, Intranets and Extranets. TikiWiki also works great as a Web-based collaboration tool. TikiWiki is a multi-purpose package with a lot of native options and sections that you can enable/disable as you need them. It is designed to be international, clean and extensible. TikiWiki incorporates all the features present in several excellent wiki systems available today plus a lot of new features and options, allowing your wiki application to be whatever you want it to be--from a simple wiki to a complex site for a whole user community with many intermediate steps. You can use TikiWiki as a forums site, a chatroom, for poll taking, and much more! The possibilities are endless.

TikiWiki’s major features include: article, forum, newsletter, blog, file/image gallery, wiki, drawing, tracker, directory, poll/survey, quiz, FAQ, chat, banner, webmail, calendar, category, ACL, and more.