Philip Greenspun of Arsdigita (http://www.arsdigita.com) is a strong proponent of AOLserver (http://AOLserver.com). He went so far as to write a great introductory document on AOLserver at http://www.arsdigita.com/asj/aolserver/introduction-1.html
Arsdigita also provides a helluva lot of free code to be used with AOLserver in The ArsDigita Community System (ACS) and OpenACS. A lot of useful stuff right out of the tarball.