http://www.perlmonks.org?node_id=126054

Q&A > CGI programming > Is it better to use off-the-shelf websites, or write my own? - Answer contributed by hacker

There's always Mantis.

I've been using it on my sites for quite some time on SourceFubar, the public CVS hosting service I run and manage. Go ahead and log in as Guest and poke around.

You can find the main site for Mantis on Sourceforge.