Try this (stupid example):

  wget -m -np -A *.txt -X */2011/* http://www.debian.org/News/

wget still traverses the entire 2011 hierarchy, even though it
should really just ignore it. As a reminder, here is the info page
entry for -X:

  `-X LIST' `--exclude-directories=LIST' Specify a comma-separated
  list of directories you wish to exclude from download (see
  "Directory-Based Limits").  Elements of LIST may contain
  wildcards.

It says "exclude from download", which may mean that it should still
crawl the contents for links to contents outside of the listed
directories. However, in the context of its counterpart -I, which
says "follow when downloading", I think the intended use is to not
follow links into the listed directories.