As mine was a clean Ubuntu installation, I needed to install certain libraries first.
sudo apt-get install g++ curl libssl-dev apache2-utils
The easiest way is to download node.js is to get a git clone. For that I needed to install the git package.
sudo apt-get install git-core
Now download node.js with git.
git clone git://github.com/ry/node.git
If you do not want to use git you could get the tar package instead.
tar -xf node-v0.1.96.tar
Now you are ready to install node.js.
sudo make install