Install Node.js from http://nodejs.org/dist/

I would not use a PPA unless it's really needed. 

Although Chris Lea's  PPA (https://launchpad.net/~chris-lea/+archive/node.js/) looks a reliable, there are some advantages to installing Node from the developer binaries, one of them is to be able to install an older version or an unstable one easily. Another one is to have imediate access to a new version, who knows exactly when the PPA will be updated after a new version is launched? 

This is a fully disposable proposal.