Very fast non-threaded Perl CGI support. Server side file caching. Very easy to install and configure. Super small - tar. Z download is under 50k.
Source code is documented and optimized for maintainability.
The server is called the MacPerl WebServer, as I wrote the original version specifically to run under the Macintosh implementation of Perl, namely MacPerl. I have finally gotten the server to the point where enough bugs are worked out so I'm not embarresed to advertise it on this list. However, I am in need of more feedback and bug reports. I have not had much time to test the server and am dependent on feedback from the outside world. If I get enough positive feedback, I will promote the current version from beta 1.0b2.7 to just 1.0.