Ask HN: Anyone know of a client package/dependency manager for javascript?

As time goes on, I seem to collect utilities libraries like underscore.js or jquery. For any project that I work on, I'd like to have the dependencies for these libraries tracked and then have them automatically added to the project that I'm working on. It seems that I end up having copies of different versions of each utility in different directories all over the place. Doing any kind of development on the underlying utilities ends up being even more painful as I end up copying things around (or using symlinks).

It makes a little bit of sense to just put everything on a central server and load them from there, but then I end up keeping track of what depends on what.

Ideally, I should be able to specify a dependency and have a package manager download the files, keep them in a central location and allow easy development (just the normal package manager features you've come to enjoy).

Does anyone know of a project like this?