This little tool will send all Trello cards in your "Done" list (or wherever you put your done cards) to your calendar, using the time and date when it was moved to the done list. This will let you see when you've completed what task, in your calendar.
git clone https://github.com/higab85/trello-cal
cd trello-cal
mkvirtualenv trello-cal
pip install -r requirements.txt
python app/setup.py
python app/main.py