Oddmuse (http://www.oddmuse.org/) is a WikiEngine. A wiki can be used for communication in a team or for documentation, when things have to be quick and easy: Content Management for everybody.
A wiki enables other people to quickly join efforts. In the office, you can introduce new employees, distribute phone lists, store memos, plan trips, document projects, prepare meetings, or describe internal processes.
For many free software projects wikis have taken an important role somewhere between manual, FAQ, IRC, and mailing lists.
Oddmuse is very easy to install. Simple installation, compact code, and easy extensibility were the most important design factors.
Easy to install; just copy one file into the correct directory and off you go.
No dependencies on version management tools or database installation.
Web server needs Perl installed; if you are allowed to run scripts, that should be a given.
Easy to use for users, easy to hack for programmers.