Phoronix: G-WAN Web Server Claims Speed Records, Features
While it hasn't been talked about much recently, still in existence and seeing new releases is G-WAN, a free but binary-only web server. G-WAN makes claims of being much faster than Apache, IIS, Nginx, and other web-serving alternatives...
A little while ago I was intrigued by GWAN's performance and decided to understand how it works. Using strace and other tools, I figured some things out and began working on an opensource alternative using just the general idea of its architecture (event-based, 1 thread per CPU, etc)... it's been a while since I've ran GWAN, but there were times my web server was actually faster -- but it isn't as feature packed, so that's not really a fair comparison. I'll perform some tests comparing with GWAN again another day.
In any case, feel free to grab it at http://github.com/lpereira/lwan (be sure to check the 'wip' branch) and try it for yourself. It's quite small (~2500 LOC of C code), runs on Linux/glibc only and does not support SSL, but I've been working on it only during my free time.