Handlebars.js is an extension to the Mustache templating language created by Chris Wanstrath. Handlebars.js and Mustache are both logicless templating languages that keep the view and the code separated like we all know they should be.
Checkout the official Handlebars docs site at...
The Mail Templating and Sending Module (part of Dragon Web Framework) for .NET that supports Handlebar Templates (HTML & plain-text), Internationalization, Summary E-Mails (Batching, i.e. do not send more than 1 email per X hours) and Asynchronous Sending.