Uki is the Ujap wiki

Uki is programmed in php. It is very simple in all aspects:

• source code
• installation procedure and configuration
• writing text and editing pages
  

The simplicity of the source code means that it does not offer too many features, but in spite of that it's quite useful.
Until I write a nice description of all features, take a look at the FeatureRequests and look for the Done section.
There are several pages of documentation available:

• InstallationInstructions and AdministratorsGuide
• UsersGuide (how to write text and maintain an Uki-hosted site)
• WikiPlugins