I'm excited you're attending the Automate ALL THE FRONT-END THINGS! workshop. We'll be discussng Sass and Grunt, during the workshop, with hands-on editing and updates of a practice site. If you can, install node and ruby before the workshop.
Node is easy to install. Go to http://nodejs.org/ click the install link and run the installer. This works on Mac, Linux and Windows.
Ruby is a little more complicated, but not much. First, see if you have it already installed: in a Terminal window, type "which ruby" and "ruby --version" If the first one returns a value and the second returns a version, you're good. If you're on a Windows box, use "where" instead of "which".
If you need to install ruby, on a Mac, you can use Homebrew (brew.sh) with $ brew install ruby, or RVM https://rvm.io. If you are nervous on the command line, use JewelryBox https://unfiniti.com/software/mac/jewelrybox
If you're on a Linux box, you can use apt or yum to install ruby (sudo apt-get install ruby1.9.1) or RVM https://rvm.io.
If you're on a Windows box, use RubyInstaller http://rubyinstaller.org/downloads/ or Pik https://github.com/vertiginous/pik
I'll review both of these at the beginning of the workshop. If you haven't installed these on your laptop, you'll have a chance to do so as I talk about the guiding principles of making workflows awesome.