I designed a really small webserver (actually about 9 of them but only one on github) because I wasn't happy with the configuration file syntax of the other opensource servers. After repeated rewrites trying to fit both fcgi and a reverse proxy I somehow managed to fit most of the things I wanted in ~107k (the lightest mainstream alternative is like 350k). I really like small programs that do their job well so for me it's a pretty good win already.
https://github.com/tiotags1/hin9/