http://wiki.github.com/frioux/Template-Tiny-js/
Because it works entirely through the creative use of regular expressions, it turns out that it is relatively easy to port as long as you have good enough regex support.
And so that's exactly what fREW Schmidt has done with his Template.Tiny JavaScript port.
Template.Tiny.js contains 600 lines of cloned code to provide an upgrade XRegexp package, and then 150 lines of plain JavaScript to implement the Template::Tiny clone.
Of course, we've already had Jemplate for a while, so it's not like you couldn't use Template Toolkit in JavaScript before.
But this gives you an alternative solution for smaller fragments that doesn't require any server side work at all and allows pure inline client-side templating, a kind of Jemplate.Tiny. :)