Cheetah is an open source template engine and code generation tool.
It can be used standalone or combined with other tools and frameworks. Web development is its principle use, but Cheetah is very flexible and is also being used to generate C++ game code, Java, sql, form emails and even Python code.
For a high-level introduction to Cheetah please refer to the User's Guide at http://cheetahtemplate.org/learn.html
"I'm enamored with Cheetah" - Sam Ruby, senior member of IBM Emerging Technologies Group & director of Apache Software Foundation
"Give Cheetah a try. You won't regret it. ... Cheetah is a truly powerful system. ... Cheetah is a serious contender for the 'best of breed' Python templating." - Alex Martelli
"People with a strong PHP background absolutely love Cheetah for being Smarty, but much, much better." - Marek Baczynski
"I am using Smarty and I know it very well, but compiled Cheetah Templates with its inheritance approach is much powerful and easier to use than Smarty." - Jaroslaw Zabiello
"There is no better solution than Cheetah" - Wilk
"A cheetah template can inherit from a python class, or a cheetah template, and a Python class can inherit from a cheetah template. This brings the full power of OO programming facilities to the templating system, and simply blows away other templating systems" - Mike Meyer
"Cheetah has successfully been introduced as a replacement for the overweight XSL Templates for code generation. Despite the power of XSL (and notably XPath expressions), code generation is better suited to Cheetah as templates are much easier to implement and manage." - The FEAR development team (http://fear.sourceforge.net/docs/latest/guide/Build.html#id2550573)
"I've used Cheetah quite a bit and it's a very good package" - Kevin Dangoor, lead developer of TurboGears.