Brail
Brail is a view engine for MonoRail which allow you to use the same framework (and language) on both ends of the application. You write the business logic using Boo (or any other .Net language), and then you write the user interface using Boo. No need for a mental switch or learn another "easy" templating language.
Brail allows the use of a fully features, powerful languague as the templating languague for MonoRail.
Here is a simple example:
${name} is the name
<%
for element in list:
output " ${element}\\r\\n"
%>
You can read more about it in the documentation secotion.
Brail is part of the Castle Project. All the most recent information, source code repository access, downloads, etc, are avialable through the Castle Project site