As of writing this article the latest node version was 4.2.4, you can install this one using the distribution from NodeSource repository:
sudo apt-get install curl curl --silent --location https://deb.nodesource.com/setup_4.x | sudo bash - sudo apt-get install nodejs
You can find all the sources here, https://github.com/nodesource/distributions/tree/master/deb
Then, you have the latest version of node.js installed.