Install Guile Scheme, a free, open-source scheme implementation available on a variety of platforms.
Install via Homebrew:
brew install guile
On most Linux distros, Guile is probably already installed as it's the official GNU extension language. If not, use your distro's package manager to install, e.g.:
sudo apt-get install guile
pacman -S guile
In ubuntu 14.04 the packages for guile are missing modules that prevent the tests from running. Guile can be installed from source under your home directory by following the instructions below.
sudo apt-get install libltdl-dev libunistring-dev libgc-dev libmpd-dev libgmp3-dev libffi-dev cd $HOME/Downloads/ wget ftp://ftp.gnu.org/gnu/guile/guile-2.0.11.tar.gz tar -zxvf guile-2.0.11.tar.gz cd guile-2.0.11/ ./configure --prefix=$HOME/lib/guile make make install if [ ! -d $HOME/bin ]; then mkdir $HOME/bin; fi ln -s $HOME/lib/guile/bin/guile $HOME/bin/guile
After installation is complete you will need to log out and back into ubuntu in order for the path to be set on your /home/bin directory.
Guile can theoretically be compiled from source under Cygwin, but as with many things, it's probably easier just to run a Linux VM.
You shouldn't need any "extra" packages.
Help us explain this better! File a GitHub issue at https://github.com/exercism/scheme/issues if you have suggestions, or submit a patch with improvements to the https://github.com/exercism/scheme/blob/master/docs/INSTALLATION.md file.