The instructions for installing roudnup behind apache using mod_python contain an incorrect RedirectMatch directive.  I was following this section of the documentation:

http://roundup.sourceforge.net/doc-1.0/installation.html#apache-http-server-with-mod-python

Using those instructions, and a bit of additional knowledge about apache, I was able to get the roundup ui to appear with my web browser.  However, the layout was all wrong.  Further investigation revealed that the RedirectMatch directive was mangling requests for style.css.  To fix it, I had to change this:

RedirectMatch permanent /roundup/([^/]+)$ /roundup/$1/

To this:

RedirectMatch permanent ^/roundup/([^/]+)$ /roundup/$1/

This was with roundup 1.3.3, apache 2.0.55, mod_python 3.1.4, and Ubuntu 6.06 (Dapper Drake).

That seems reasonable - I've patched the docs.