Fixed a bug in my tweaked jython servlet. From the comments:

 *
 * This is a copy of the PyServlet that comes with jython, with the
 * following enhancements (written by Phil Dawes - pdawes@users.sf.net):
 *  
 * - It will try appending .py to the URL - e.g. /foo/bah resolves to
 * the jythonservlet at /foo/bah.py
 *
 * - It can take a 'defaultservlet' init parameter to specify a
 * jythonservlet to invoke if it can't map the URL to a regular
 * servlet
 *
 * - It adds the directory of the jythonservlet to sys.path, to allow
 * nested servlets to import modules in their nested directory

Get it from here