Contracts.coffee Works In Node.js!
You'll need a bleeding-edge version of node to get it running. Try either master (unstable) or 0.5.7. Build instructions are here.
Proxies are hidden behind a command line flag in V8 so you'll also need to supply
--harmony_proxies to node when calling the compiler:
node --harmony_proxies bin/coffee -CL test.coffee
There are almost certainly node-specific bugs in contracts.coffee so don't trust it with anything important yet. You can get started playing though!
Report any bugs you run into on the issue tracker.