Ask HN: What options are there for executing untrusted code in Node.js?

Over the past couple of weeks while prototyping various ideas I've kept on running into a hurdle when it comes to trying to run untrusted JavaScript code in Node.JS.

One solution I found early on was Sandbox (http://gf3.github.io/sandbox/), which seems to be fairly safe security wise, but doesn't offer much else.

Node.JS also has a vm module (http://nodejs.org/api/vm.html), but it it is 'Unstable'.

I've also come across sandboxed-module (https://github.com/felixge/node-sandboxed-module), however I can't figure out what it actually does, and also js.js (https://github.com/jterrace/js.js), but it's much too slow to be of much use.

So, does anyone else know of any other solutions?