Here’s the source article:
http://www.frederico-araujo.com/2011/07/30/installing-rails-on-os-x-lion-with-homebrew-rvm-and-mysql/

My goals here are to update an environment and move to a new Susy release: http://susy.oddbird.net/

1. Install and upgrade XCode from the Mac App Store (4.3.2 in this case). Also install the Command Line Tools found in the Preferences pane.

2. Install Homebrew. Not entirely necessary, but I’m enjoying it lately.

Install Homebrew Package Manager

$ /usr/bin/ruby -e "$(/usr/bin/curl -fsSL https://raw.github.com/mxcl/homebrew/master/Library/Contributions/install_homebrew.rb)"

Install Homebrew Package Manager
$ /usr/bin/ruby -e "$(/usr/bin/curl -fsSL https://raw.github.com/mxcl/homebrew/master/Library/Contributions/install_homebrew.rb)"

3. Install RVM – Ruby Version Manager

// Install RVM
$  bash -s master < <(curl -s https://raw.github.com/wayneeseguin/rvm/master/binscripts/rvm-installer)
// Reset some paths
$ echo '[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm" # Load RVM function' >> ~/.bash_profile
// Run to reset your open terminals
$ source ~/.bash_profile
// Make sure RVM is updated
$ rvm get stable
// Had to do a reinstall for Ruby stable
$ rvm reinstall 1.9.3-p194
// Use Ruby 1.9.3-p194
$ rvm use 1.9.3-p194 --default
// Check my ruby version
$ ruby -v

4. Install Compass

// Make sure all is good
$ sudo gem update --system
// Some XML Tools
$ sudo gem install builder
// Install Compass
$ sudo gem install compass
// Here's where things went wacky, so Installed the kitchen sink - over-install-panic-attack!
$ sudo gem install haml
$ sudo gem install haml-edge
$ sudo gem install rails
// Oh it's a damn bug see:
// http://stackoverflow.com/questions/10610254/cant-install-compass-via-rvm
$ rubygems-bundler-uninstaller
// Test Compass
$ compass version

5. Install my favorite Compass add-ons

// Oily_PNG to for sprite creation performance
$ sudo gem install oily_png
// Susy because grids are awesome - Now this will install some alpha SASS and Compass code but why not.
$ sudo gem install susy --pre
// Normailze CSS sortof-reset
$ sudo gem install compass-normalize