growlcoffee with npm:
npm -g install growlcoffee
-r growlcoffee to your
coffee commands. For example here is the commend to watch and compile the coffeescript files in the current directory:
coffee -r growlcoffee -w -c .
Whenever a file is updated a growl notification will occur letting you know if the compilation was successful or if there was a problem.
growlcoffee is distributed under the MIT License.