And again for templates
Markaby for Rails: why the lucky stiff and Tim Fletcher have released a pretty cool templating language for Rails called Markaby that looks like Builder, but assumes a few more things to make it even more succinct and targeted against HTML
Radius is a small, but powerful template language for Ruby inspired by the template languages used in MovableType and TextPattern. It uses tags similar to HTML, but can be used to generate any form of plain text (XML, e-mail, etc…).