Add calendar events when triggered to your todo.txt Dropbox file

If

Any event starts

This Trigger fires a set number of minutes before the starting time of any event on your Google Calendar. Note: The time in the ingredient will be based on the timezone set in Google Calendar.

Then

Append to a text file

This Action will append to a text file as determined by the file name and folder path you specify. Once a file’s size reaches 2MB a new file will be created.