Chuck Lever and company have written a nice paper that talks about queued signals and phhttpd. While hacking on it they found many bugs and submitted fixes. Releases since 0.1.1 have been based almost entirely on Chuck's clean ups. Chuck has since moved on to other things, but I want to thank him for his help. Matofali was intended to be the web server that phhttpd always wanted to me.
Archives are also available.
Apache RPMS included. The two servers establish a line of communication while running. If it can't parse the request for whatever reason, it hands the connection over its line to the backing server for it to process. It uses this to greatly reduce the amount of processing that must be done per request. It also features a non blocking event model that allows a single thread to serve many connections.