Application

C Server Pages
An application server that supports building web applications using C++ and templates with dynamics elements embedded. Supports Linux. By T. Gonzalez.
http://cserverpages.20m.com/

Helma
A Java based application server which is using ECMA-Script as its scripting language. [Open source, BSD style license]
http://www.helma.org/

NGASI Application Server
Turnkey Next Generation Application Server solution for Web and Wireless Application Hosting and enterprise environments such as ISPs and IT Departments.
http://www.ngasi.com

SQLData Enterprise Server
A web application server that combines web services and database services together. It provides session management, multi-level authentication, data encryption, load distribution and custom logics. By SQLData Systems, Inc.
http://www.sqldata.com/enterprise.htm

UserLand Frontier
Frontier is a full featured application server that connects to XML-RPC and SOAP services. It includes an object database, multithreaded runtime, a content management system, and a bundled http server. It costs $899.
http://frontier.userland.com

WebCollage Syndicator
Enables businesses to syndicate complete, interactive Web applications and services to partner sites, allowing new forms of Web partnerships. By WebCollage, Inc.
http://www.webcollage.com/

WebHub
An application server that is designed for integration with applications developed in Inprise Delphi. By HREF Tools Corp.
http://www.href.com/

WebObjects
Tool for web application development and deployment. Currently available on *nix, WinNT, and Mac OS X. By Apple Computers, Inc.
http://www.apple.com/webobjects/