Node.js is available in official gentoo portage tree. You have to unmask it.

# emerge -aqv --autounmask-write nodejs
# etc-update
# emerge -aqv nodejs

Node.js is available in official repo for Debian Sid(unstable).

For Debian Squeeze, your best bet is to compile node by yourself (as root):

apt-get install python g++ make
mkdir ~/nodejs && cd $_
wget -N http://nodejs.org/dist/node-latest.tar.gz
tar xzvf node-latest.tar.gz && cd `ls -rd node-v*`
./configure
make install

How to install node.js on Debian-based Linux distros (Debian, Ubuntu, Mint etc)

Example install:

sudo apt-get install python-software-properties
sudo add-apt-repository ppa:chris-lea/node.js
sudo apt-get update
sudo apt-get install nodejs npm

It installs current stable Node on the current stable Ubuntu. Quantal (12.10) users may need to install the software-properties-common package for the add-apt-repository command to work: sudo apt-get install python-software-properties

If you want to compile Node C++ modules:

sudo apt-get install nodejs-dev

Or configure shell script for install node.js using http://apptob.org

Node.js stable repos list. Also node.js is available in openSUSE:Factory repository.

Available RPM packages for: openSUSE 11.4, 12.1, Factory and Tumbleweed; SLE 11 (with SP1 and SP2 variations).

Example install on openSUSE 12.1:

sudo zypper ar http://download.opensuse.org/repositories/devel:/languages:/nodejs/openSUSE_12.1/ NodeJSBuildService 
sudo zypper in nodejs nodejs-devel

On http://nodejs.tchol.org/ there was previously an updated yum repository, but it hasn't been updated since May 2012.

Node.js is available in the Community Repository.

pacman -S nodejs

Node.js is available through the ports system.

/usr/ports/www/node

Development versions are also available using ports

cd /usr/ports/www/node-devel/ && make install clean

or packages on FreeBSD

pkg_add -r node-devel

Using a package

Simply download Macintosh Installer.

Using homebrew:

brew install node

Warning: brew installs are known to be buggy

Using macports:

port install nodejs  

Using a package

Simply download Windows Installer.

Using chocolatey to install Node:

cinst nodejs  

or for full install with NPM:

cinst nodejs.install