nginx - A high performance free open source web server powering busiest sites on the Internet.
Apache HTTP Server - Apache httpd has been the most popular web server on the Internet since April 1996
Cherokee - High-performance web server
lighttpd - A secure, fast, compliant, and very flexible web-server that has been optimized for high-performance environments
Apache Tomcat - An open source software implementation of the Java Servlet and JavaServer Pages technologies
Wt - Wt (pronounced as witty) is a C++ library for developing web applications.