Baler is no longer in active development. I recommend you look at Cassette if you want something in active development.
Baler is a Web Resource Bundler for .NET. Baler can be used to concatenate CSS or JavaScript files with hooks that allow for manipulation of the bales. These hooks can be used to provide minification of the content or allow for language dialects to be used such as CoffeeScript or LESS. Baler can be used within WebForms and ASP.NET MVC (as well as any other web framework view engine that supports execution of server side code). It uses a semi-fluent API to ensure code is clean and readable.
See "the Baler project site":http://yobriefca.se/projects/baler for instructions.