Mustache is a framework-agnostic way to render logic-free views
https://github.com/mustache/mustache

Inspired by ctemplate, Mustache is a framework-agnostic way to render
logic-free views.
As ctemplates says, "It emphasizes separating logic from presentation:
it is impossible to embed application logic in this template
language.
Think of Mustache as a replacement for your views. Instead of views
consisting of ERB or HAML with random helpers and arbitrary logic,
your views are broken into two parts: a Ruby class and an HTML
template.