This program uses the Google Calendar API to provide custom reports on your own calendars.
Or, more realistically at this point, it attempts to show how to integrate that API in a Silex Framework application.
Unpack it to lib/google-api-php-client like:
cd lib ; tar xf google-api-php-client-0.6.7.tar.gz
php composer.phar install to download and install all Composer-controlled
Regrettably, none of the Packagist packages for the Google API PHP Client appears to be reasonably up to date currently, hence the separate downloads.