To use compass project requires gem zen-grids

LoadError on line ["45"] of /usr/lib/ruby/site_ruby/1.9.1/rubygems/core_ext/kernel_require.rb: cannot load such file -- zen-grids
Run with --trace to see the full backtrace

^ for people googling the error message.

If you see this it is because you do not have the zen-grids gem installed running:

gem install zen-grids

will fix your issue.

I propose mentioning on the project page that you need the zen grids gem using the code callout so it stands out.