ColdFusion (Adobe proprietary, formerly Macromedia)
CGI and/or Perl (open source)
Groovy (programming language) Grails (framework)
Java, e.g. Java EE or WebObjects
Lotus Domino
PHP (open source)
Python, e.g. Django (web framework) (open source)
Ruby, e.g. Ruby on Rails (open source)
Smalltalk e.g. Seaside, AIDA/Web
SSJS Server-Side JavaScript, e.g. Aptana Jaxer, Mozilla Rhino
Websphere (IBM proprietary)
.NET (Microsoft proprietary)