Google Spreadsheet Diff
This is a collection of scripts (bash and Python) that help automate and record the changes to a Google Spreadsheet.
The basic flow is that the Google Spreadsheet is accessed, read, and written to a CSV file. The excellent csvdiff is then used to check for changes, and the changes are then appended to a changelog with timestamp.
You can use cron to automate this further.
You will need to download/install the csvdiff file from here: https://pypi.python.org/pypi/csvdiff
You will also need to enable the Google Drive API and get your service account setup. I used this very nice guide by Chris Moffitt as a starting point for the Google stuff: http://pbpython.com/pandas-google-forms-part1.html
Make sure you edit the appropriate areas of the scripts :) As this was set up to be automated the script does not prompt the user for information.
You can just run the python script on it's own and then run csvdiff manually. The bash script is designed to run in cron and write all changes to a changelog file.