A web server from W3C. Distributed under W3C's open source license. It is intended as W3C's reference implementation of standards like HTTP and WebDAV.

Jigsaw is written entirely in Java and has support for Java plugins, servlets, and other things like that. It can also be configured to support PHP and, naturally, also does CGI. Configuration is done with Swing-based configuration tool (that is still somewhat cryptic if you don't know its own terminology).

While it ain't Apache, it's still a pretty nice server and easy to set up even in Windows - and it seems pretty fast for being written in Java. Looks like this "JIT" thing actually works! =)

Home page: http://www.w3.org/Jigsaw/