So, with something like Tower.js the code is written in coffee to start with (https://github.com/viatropos/tower/tree/master/src), but in the repo (and in npm) you'll actually get the resulting JavaScript as well (https://github.com/viatropos/tower/tree/master/lib and https://github.com/viatropos/tower/tree/master/dist).

This is generally true of most CS projects. I can't speak specifically to whether or not you can use Tower.js without coffee, just saying don't discount a project because the author wrote it in CS. Spine.js (http://spinejs.com) is a great example of what I'm talking about.