Hudson is pretty easy to deploy and the ability to add to an existing web server
is something that needs to be kept, but...

Consider Fit Nesse.

http://fit.c2.com/wiki.cgi?FitNesse
ttp://fitnesse.org

To run it, you download the archive, unzip it, and double-click run.bat or
run.jar. The easier deployment can be made, the more users you will have.

Web Start is also worth considering, but has transportability issues in my mind.
Fit Nesse stores all of its files under the directory it was unzipped to.
Redeploying to a different machine is potentially as easy as copying a file
tree. A Web Started Hudson could serve a Web Start page for spawning someplace
else, but I don't know of any application that currently does that, so there
might be some unexpected difficulties there.