Node.js has been added as an available package in Fedora 18. Note that it is currently only in Rawhide and Updates Testing repositories. So, to install, first make sure that Updates Testing repo is enabled and then install nodejs package.
sudo yum install nodejs --enablerepo=updates-testing
After that install NPM:
git clone https://github.com/isaacs/npm.git
sudo make install
Finally, install sugar-on-top CoffeScript:
sudo npm install -g coffee-script
More info on available packages: RPM resource nodejs