CGILua is a tool for developing dynamic HTML pages and manipulating input data from forms. It uses the interpreted language Lua for codifying its scripts. It has been on the road for almost 8 years now, being used in many Web products and sites. It is extensible through Lua libraries and dynamic loading of C/C++ libraries. Scripts can be written as Lua programs or HTML templates (HTML with Lua code embedded). Scripts are platform-independent.
Twisted is an event-based framework for Internet applications. It includes a Web server, an SMTP/POP3 server, a telnet server, an SSH server, an IRC server, a DNS server, a generic client/server pair for remote object access (Perspective Broker), and APIs for creating new protocols. It supports integration with GTK+, GTK+ 2, Qt, Tkinter, wxPython, Mac OS X (PyObjC) and Win32 event loops. It also supports TCP, SSL and TLS, UDP, Unix sockets, multicast, and serial ports. Supported protocols include HTTP, FTP, SMTP, POP3, IMAP, TOC, OSCAR (AIM and ICQ), SSH, DNS, IRC, NNTP, Jabber, SOCKSv4, Telnet, SIP (for VoIP), and XML-RPC and SOAP using external packages. Most protocols are supported as both servers and clients.
XIST is an extensible HTML and XML generator. It is also an XML parser with a very simple and Python-esque tree API. Every XML element type corresponds to a Python class, and these Python classes provide a conversion method to transform the XML tree (e.g. into HTML). XIST can be considered 'object-oriented XSLT'. XIST also includes a cross-platform templating language, Oracle utilities, and various other tools.
Cheetah is a Python-powered template engine and code generator. It can be used as a standalone utility or it can be combined with other tools. Web developers are its principle user group, but it has many potential uses and is also being used to generate C++ game code, Java, SQL, form emails, and even Python code.