HTML::LinkList is a perl module containing function to help make "smart" lists of links in HTML. It isn't limited to presenting the links as just a list; the formatting has many options. The lists are "smart" because if you tell them what your current (relative) URL is, they will make a label rather than a link if that URL is in your list of URLs.
This is such a commonly desired ability, and yet there didn't seem to be a module on CPAN for it. Sure, are were plugins here, there, and everywhere for specialized HTML systems which do fancy navbars, but everyone seemed to be reinventing the wheel. I hereby present one wheel, free to be reused by anybody; just the simple functions, a backend, which can be plugged into whatever system you want.
For example, I use perl on this site, and use this module to generate the navigation on all pages and for the Site Map. Note that it depends on other code to actually create the list of links (and descriptions) which it processes.