My time-tables are provided in the ICal-format. Since my time-tables had changed, I wanted to reimport the .ics-file for that course in my Google Calendar after deleting them first. Trying to do so gave the error:
Failed to import events: Some of the events in this file were not imported because you had imported them to Google Calendar before. Other events in this file have been imported..
Apparently Google prevents you from (accidentally?) importing the same appointments twice. However, I wanted to import them anyway. Luckily for me, Google only checks the UID. Since all my UID's started with UID:INBPC-08, I did a find and replace all on the text, and changed it to UID:INBPC-09. Now GCal was able to import them again 🙂