PageOfText is a bare bones single page wiki written by Gordon McCreight. It is primarily a service where you can easily create a page to use on your own or to collaborate with others. If you wish, you can also install it on your own machine. It is written in Perl, and the source is available as a mainly GPL bundle (some Artistic code is also packaged with it). Here is the tarball
In order to use Creole as a page's markup, you have to specify it in the "advanced options". Otherwise the page is just plain text.