WikiClone is a clone of WardCunningham 's WikiWikiWeb.
Perl Sourcecode and example templates are available via anonymous ftp from ftp://ftp.jos.org/pub/wiki.zip and ftp://ftp.jos.org/pub/exampletemplates.zip
Note that there's no documentation and that it's rather hard to setup. Help make it easier and join the HowToInstallJosWiki group.
According to WikiWiki GoodStyle and WhyWikiWorks (despite BillRehm's ideas), creating incomplete solutions is the way to get better one. This, added to the fact that setting up JosWiki alias WikiClone is recognized as being though, triggered me to add some pages, and to move signed text to them. HowToInstallJosWiki may be a good start
FindPage will allow you to search for topics that interest you.