BlastJS
Blast is a powerful library for creating user interfaces by writing reactive HTML templates. Compared to using a combination of traditional templates and jQuery, Blaze eliminates the need for all the "update logic" in your app that listens for data changes and manipulates the DOM. Instead, familiar template directives like {{#if}} and {{#each}} integrate with Tracker's "transparent reactivity" and Minimongo's database cursors so that the DOM updates automatically.
Read more on the Blaze Project.